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Stentor, Its Cell Biology
and Development
Sarah B Reiff, University of California San Francisco, San Francisco,
California, USA
Wallace F Marshall, University of California San Francisco, San Francisco,
California, USA
Advanced article
Article Contents
•Introduction
•The Cell Biology of Stentor
•The Contractile Response and Habituation
•Single Cell Regeneration in Stentor
Online posting date: 16th February 2015
Stentor comprises a genus of freshwater protists
that has long enthralled cell and developmental
biologists. These organisms are large polyploid sin-
gle cells that possess highly polarised and complex
structures. Normally elongated in a trumpet-like
shape, Stentor cells also have the ability to contract
their cell body, and do so in response to mechan-
ical or light stimuli. Interestingly, this response is
subject to habituation, meaning the cell can ‘learn’
after repeated exposure to ignore these stimuli
and stay elongated. Perhaps the most remark-
able characteristic of Stentor is the ability of these
cells to fully regenerate after being cut in half,
perfectly preserving the original cell structure.
Numerous microscopic studies analysed the minute
morphological details of Stentor regeneration, but
for many decades, there were no tools available
for molecular and genetic studies. However, recent
developments should now allow researchers to
probe the molecular details of regeneration in a
single-celled organism.
Introduction
Protists of the genus Stentor have been fascinating microscopists
and developmental biologists for more than a hundred years.
Stentor belongs to the phylum Ciliophora, which contains other
model protists such as Tetrahymena, in which telomeres were
rst discovered, and Paramecium, the well-known pond water
organism. One of the rst descriptions of Stentor was penned by
Abraham Trembley back in 1744, who discovered them study-
ing pond water with a microscope and called them ‘funnel-like
polypes’. Later, in the nineteenth century, they were classied
into the genus Stentor, named after the Greek herald for their
eLS subject area: Cell Biology
How to cite:
Reiff, Sarah B and Marshall, Wallace F (February 2015) Stentor,
Its Cell Biology and Development. In: eLS. John Wiley & Sons,
Ltd: Chichester.
DOI: 10.1002/9780470015902.a0025978
trumpet-like shape. Then, around 1901, the famous embryologist
Thomas Hunt Morgan performed experiments on Stentor and
found that these cells could fully regenerate after being cut apart
(Morgan, 1901). T. H. Morgan and others, including the biologist
Vance Tartar, performed numerous microscopy experiments on
Stentor, cutting them in half to stimulate regeneration, and even
grafting multiple Stentors together to examine how cell growth
and development is affected (Tartar, 1961). As a result, knowl-
edge about the regeneration and morphological development of
Stentor is very nely detailed from the perspective of surgical
manipulations. However, starting around the 1970s and 1980s,
the amount of studies using Stentor began to wane. This was a
period when biochemical techniques were becoming very popu-
lar. To be able to purify proteins and other components from cells,
it is necessary to harvest very large quantities, but Stentor cells
typically do not grow very densely and thus seemed to be a poor
model system for the biochemical era. Now, however, molecu-
lar biology tools are becoming more and more advanced, and it
has at last become possible to uncover the molecular and genetic
details of the single cell regeneration process in Stentor.See also:
Ciliophora;Tetrahymena;Paramecium
The Cell Biology of Stentor
Many different species of Stentor exist, most of which have
similar cell body patterning, but they vary greatly in size and
colour. Here, we focus on Stentor coeruleus,asthisisthespecies
that has been studied to the greatest extent. S. coeruleus is the
largest of the Stentor species, blue-green in colour and visible to
the naked eye, reaching 1 mm in length when swimming and over
2 mm when fully extended.
General structure and organisation
of the cortex
Stentor cells are highly polarised and complex structures
(Figure 1), and their biology is in many ways very different from
animal cells and yeast. Much of this complexity and polarity
is patterned on the cell cortex, making these features easily
visible on a light microscope. The cortex of a cell consists of
the cytoskeletal components that lie under the cell’s plasma
membrane, and help give the cell its shape and appearance. A
member of the phylum Ciliophora, Stentor is a ciliate, and like
other ciliates, the Stentor cortex possesses many parallel rows
of cilia that extend from the anterior to the posterior end of the
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Stentor, Its Cell Biology and Development
Frontal field
Membranellar band
Food vacuole
Wide granular stripe
Thin granular stripe
Clear stripe
Macronucleus
Holdfast
Ramifying zone
Oral pouch
Gullet
Figure 1 Diagram of an S.coeruleus cell. The frontal field, membranel-
lar band and oral pouch comprise the oral apparatus at the anterior end of
the cell, and the cell terminates in a holdfast at the posterior end. Extending
longitudinally from the anterior to posterior end are ciliary rows, bordered by
a dark pigmented cortical stripe on one side and a clear cortical stripe on the
other. The pigmented stripes are graded in width, and the area where the
wide stripes abut the thin stripes is the ramifying zone. The transcriptionally
active polyploid macronucleus (blue) is a single continuous organelle that
appears as a series of connected nodes and extends through most of the
length of the cell. The micronucleus is not pictured but consists of multiple
tiny organelles closely associated with the macronucleus.
cell. When examining the cell under a microscope, alternating
dark stripes and clear stripes can be observed. The dark stripes
appear dark because of pigment granules beneath the surface
that contain the pigment stentorin. The clear stripes contain the
longitudinal rows of cilia. The surface of the cortex is not com-
pletely smooth but possesses longitudinal ridges. The pigmented
stripes make up the ridges of the cortex, whereas the clear stripes
are found in the corresponding valleys. Stentor and its striping
are also not radially symmetric. If an observer were to examine
Stentor’s stripes in a clockwise manner, starting on the ventral
side, the clear stripes start out being close together and they
gradually become farther apart as the dark stripes increase in
width. Eventually, the wide stripes come into contact with the
narrow stripes. This line is called the locus of striped contrast or
the ramifying zone (Tartar, 1961).
The ciliary rows found in the clear stripes are characteristic of
ciliate organisms and are sometimes known as kineties in this
phylum. Like cilia and agella in other organisms, each cilium is
anchored by a basal body or kinetosome. The basal bodies in each
row are found in pairs (the anterior one ciliated and the posterior
one unciliated) and are connected by a bre called the km-bre.
Each km-bre consists of a series of stacked microtubules (Huang
1 mm
Figure 2 Dynamic cell shape of Stentor cells. When swimming, Stentor
cells tend to be around 0.5–1 mm long and exhibit an aquadynamic shape
(large inset). When anchored, however, the cells can extend themselves
to much greater lengths, even reaching closer to 3 mm, as shown in the
cells in the background image. The cells also exhibit a contractile response
upon mechanical or photo-stimulation (small inset), in which the cell shape
becomes much more rounded and length decreases to around 0.25 mm.
Image is to scale.
and Pitelka, 1973). These microtubules originate from the basal
bodies and are thus considered post-ciliary microtubules. This
is in contrast to other ciliates, in which the post-ciliary micro-
tubules are very short, and the basal bodies are instead connected
by the non-microtubule-based kinetodesmal bre, which is absent
in Stentor (Frankel, 1989). The cell also possesses another set of
longitudinally oriented bres called myonemes, which are asso-
ciated with the km-bres but appear less orderly in their align-
ment. The myonemes consist of densely packed laments, whose
molecular composition is largely unknown, although centrin
orthologues have been identied there (Maloney et al., 2005).
The primary function of the myonemes is most likely to facili-
tate contraction of the cell. Transverse bres connecting adjacent
myonemes have been observed and are more common towards
the posterior end of the cell than the anterior end.
The posterior end of the cell terminates in a holdfast, which the
cell can use to attach to an object and stay stationary. This can
be benecial when the cell is in an environment rich in food, as
it can stay in one place and lter feed without expending much
energy. In this state, the cell usually starts to extend so that its
feeding organelles are farther away from where the holdfast is
anchored, and thereby takes on the characteristic trumpet-like
shape for which the genus was named (Figure 2). The cell can
also detach at will and swim around by beating the body cilia.
When swimming, the cell contracts the cell body somewhat,
allowing its shape to be more aquadynamic and conducive to
swimming quickly. The cells swim in a more or less straight
line, rotating along the anterior–posterior axis, but can change
direction by temporarily reversing the ciliary beat, allowing the
cell to move backwards slightly and reorient to a new direction.
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Stentor, Its Cell Biology and Development
At the anterior end of the cell are its feeding organelles, often
termed the oral apparatus. The oral apparatus is ringed by a series
of structures called membranelles. Each membranelle consists
of a short row of cilia, which are stuck together so that they
become planar rather than linear, and together the membranelles
are arranged in parallel orientation around the anterior facet of
the cell cortex to form the membranellar band. One end of the
membranellar band terminates in an oral pouch, into which the
cell can funnel water containing food. Beneath the oral pouch
is the cell’s gullet, where it internalises its food into vacuoles to
later digest. The rest of the anterior end of the cell, inside the
membranellar band, is arranged into dark and clear stripes and
termed the frontal eld. These stripes follow the contour of the
membranellar band.
Macronucleus and micronucleus
Like other ciliates, and in contrast to many other cells, Stentor is
binucleate and contains a macronucleus and micronucleus. In cil-
iates, the micronucleus is the germline nucleus and contains the
DNA involved during mating. However, it is mostly transcrip-
tionally silent. The macronucleus does not participate in mating
or meiosis but is the transcriptionally active nucleus from which
genes are expressed.
In ciliates, the macronuclear genome tends to be polyploid. In
the related ciliate Tetrahymena thermophila, the copy number is
around 45 (Eisen et al., 2006), and in Paramecium tetraurelia,the
copy number is around 800 (Duret et al., 2008;Swartet al., 2013).
In S.coeruleus, although the exact copy number of the macronu-
clear genome is not known, it is predicted to be several thousand.
In addition, instead of a typical ovoid nucleus, the macronucleus
in S.coeruleus is moniliform, meaning that it is a single continu-
ous organelle that consists of several connected nodes extending
along the length of the cell. As the cell is very large, perhaps
this morphology helps RNA transcripts disseminate throughout
the cytoplasm more quickly. The nodes of the micronucleus are
much smaller and do not appear connected but tend to be in close
proximity to the macronuclear nodes.
Cell division
Ciliates are sexual organisms and can sexually reproduce in a
process known as conjugation. In Stentor, however, while conju-
gation has been reported, it seems to occur less frequently than in
other ciliates like Tetrahymena. Much more often, the cells repro-
duce asexually by binary ssion, but as the cell structure is so
complex and polarised, the middle part of the mother cell must
rst undergo some differentiation to create the precursors to the
new holdfast and feeding organelles.
Cell division in Stentor has been previously described as a
progression through eight or nine stages (Figure 3)(Tartar,1958,
1961), and the major event in the rst half of these stages is the
generation of the new feeding organelles. In stage 0, some of the
narrow dark stripes adjacent to the locus of striped contrast begin
to split, and this is the rst visual indication that the cell is initiat-
ing division. In stage 1, the split region of stripes widens further to
create a diagonal zone of clearing known as the oral primordium.
Next, in stage 2, the oral primordium begins to get longer and
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456
78 9
Figure 3 Stages of cell division in Stentor. The first three stages show
the development of the new oral primordium, where the new membranellar
band will form. In stages 3 and 4, cilia begin to grow from the oral
primordium, and in stage 5, it begins to curl as the new oral starts to form at
the posterior end of the new band and the macronucleus begins to coalesce.
In stage 6, the fission line appears, cutting across the cell’s longitudinal
striping. In stage 7, the fission line and new membranellar band migrate
slightly posteriorly as the congealed macronucleus stretches between the
two new daughter cells, and in stage 8, the fission line continues to constrict
until fission occurs and cytokinesis is complete. Reproduced with permission
from Tartar, 1958. © John Wiley & Sons.
starts to curve at the anterior end. Then, as the primordium is
still increasing in length, it starts to develop cilia. By stage 4,
the primordium has nearly reached its full length, and the cilia
are now full length and organised into the membranelles, which
begin to beat. In stage 5, the nodes of the macronucleus gradually
start to get closer together and begin to fuse, and an additional
small clearing zone can be observed at the posterior end of the
oral primordium, where the oral pouch will eventually form.
In the nal stages of cell division, the division furrow nally
begins to form. It is rst observed in stage 6, when the posterior
end of the newly forming membranellar band has curved inward
to begin forming the oral pouch and gullet, and the macronucleus
has become a compact mass. In stage 7, the oral primordium
begins to curve further, and the macronucleus elongates and
stretches between the two developing daughter cells. The cell
cortex also begins to pinch at the region of the division furrow.
Then, in the nal stage, the new membranellar band is now
curved around the anterior end of the posterior daughter cell. The
macronucleus has divided between the cells and is separating
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Stentor, Its Cell Biology and Development
once again into nodes, and the division furrow is constricted
enough to form the new posterior pole of the anterior daughter.
The daughter cells are now fully developed, with the posterior of
one daughter protruding from the anterior of the other, and then
ssion completes the cell division process (Figure 3).
The Contractile Response
and Habituation
Contraction and extension
Stentor cells have a great ability to alter their cell shape by extend-
ing or contracting (Figure 2). When anchored, they often extend
to reach lengths as long as 2 mm or more. While swimming, they
contract the cell body somewhat, but they also exhibit a contrac-
tile response in reaction to light, mechanical or electrical stimuli.
This is an all-or-none response that causes them to round up into
a ball-like shape. They cannot properly feed in this state, but they
become harder for other organisms to prey upon.
The contraction of the cell body is mediated by the myonemes
(Huang and Pitelka, 1973) and occurs very quickly, the whole
process taking only 20 ms or less (Wood, 1970). Transmission
electron microscopy has shown that in an extended state, the
laments of the myoneme are all oriented longitudinally and
parallel to each other. In a contracted state, their orientation along
the cell axis still appears mostly longitudinal, but they are no
longer organised parallel to each other and appear much more
jumbled (Huang and Pitelka, 1973). Cell body contraction has
been studied in greater depth in the related ciliate Vorticella and
is known to be calcium-mediated. See also:Vorticella
To re-extend the cell body, Stentor relies primarily on its
km-bres, also running longitudinally. The microtubules in the
km-bre with the help of motor proteins are able to slide against
each other, ultimately making the cell longer. The individual
microtubule ribbons in the bres are around 24 μm in length, but
if each ribbon slides only 2 μm relative to its adjacent ribbon, the
cell can gain a fourfold increase in length (Huang and Pitelka,
1973). The process of re-extension takes much longer than con-
traction and generally occurs over several seconds.
Habituation
Stentor cells also have the ability to habituate to mechanical,
electrical and light stimuli, such that after repeated exposure
they no longer exhibit the typical contractile response. This is
considered a type of non-associative learning and is observed in
all animals. One notable example is the sea slug Aplysia cali-
fornica, which when disturbed will withdraw its gill and siphon,
but after repeated disturbances becomes much less likely to react.
Eric Kandel studied the neural circuitry involved in this response
in the sea slug and was awarded a Nobel Prize for his work in
2000 (Klein and Kandel, 1980). Observations of habituation in
single-celled organisms such as Stentor, however, demonstrate
that this phenomenon can also be generated on smaller scales
and does not require a multicellular nervous system. It is there-
fore possible that parallels exist between the physiology of animal
neurons and of complex single-celled organisms like Stentor.See
also:Molluscs: Learning and Memory
Habituation in Stentor was rst observed by H. S. Jennings in
1906 (Jennings, 1906). This habituation does not apply across
different types of stimuli – for example, if a Stentor cell becomes
habituated to mechanical stimuli such that it no longer contracts
when touched, it will still contract in response to electrical stim-
uli or intense light (Wood, 1969). This is because the original
stimulus is detected by different types of receptors in the cell
membrane – mechanoreceptors for touch and photoreceptors for
light – and the habituation of the cell happens at the level of the
receptors. This also indicates that the contractile machinery is not
affected during habituation. In addition, the cell will still contract
in response to stronger stimuli of the same type. Finally, as seen in
habituation in animals, if the cell is allowed a rest period in which
it is not stimulated, the cell becomes dishabituated and begins
responding to stimuli as it did originally. In Stentor,aftera1h
rest period, the probability the cell will contract in response to a
stimulus is markedly increased (Wood, 1969), and this probability
gradually increases with longer rest periods.
In the case of mechanical stimuli, the contraction and habitua-
tion response is caused by mechanoreceptors. The initial stimulus
causes the mechanoreceptors to open a channel to let calcium
ions in, which in turn changes the receptor potential. If the recep-
tor potential is high enough, this may elicit an action potential.
Electrophysiology studies in Stentor have shown that when action
potentials are elicited during repetitive stimulation, the ampli-
tude of the receptor potential decreases in subsequent stimulation
(Wood, 1988a,1988b), and that these decreases do not occur if an
action potential is not elicited. This decrease in receptor poten-
tial is responsible for the habituation response. After an action
potential, the receptors take on a conformation in which the chan-
nel becomes more highly voltage-dependent and is less likely
to open in response to a stimulus. Cell contraction in ciliates is
known to be calcium-dependent (Ishida et al., 1992; Iwadate and
Nakaoka, 2008; Weisfogh and Amos, 1972), so once a signicant
proportion of mechanoreceptors are in this closed conformation,
the inux of calcium into the cell will not be enough for contrac-
tiontooccur.
Single Cell Regeneration in Stentor
Most of the current research on animal regeneration is focused
on the differentiation of stem cells to replace lost cell types,
but it is equally interesting to examine how a single cell can
regenerate parts without the whole cell needing to be replaced.
Stentor is an excellent model system to probe this question due to
its remarkable capacity to regenerate parts at a subcellular level.
Furthermore, its large size allows scientists to perform operations
to cut cells into pieces or even graft pieces of different cells
together, allowing detailed experimentation to determine which
parts of the cell are required for regeneration.
Oral regeneration after sucrose shock
When Stentor cells are exposed to a sucrose solution, they shed
their oral apparatus and begin regenerating a new one. The oral
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Stentor, Its Cell Biology and Development
regeneration process takes about 8 h and is very similar to the
way in which the cell generates a new oral apparatus during cell
division. Interestingly, the nodes of the macronucleus also coa-
lesce during oral regeneration as during cell division, and then
renodulate without undergoing ssion. This may suggest that oral
regeneration is the result of some of the same molecular pathways
involved in cell division and that the regeneration capabilities of
Stentor are perhaps due to its ability to activate these cell division
biogenesis pathways at will. Oral regeneration is also sensitive to
certain antagonists of calcium and calmodulin, including vera-
pamil, W-7 and triuoperazine (Maloney et al., 1991). Although
the molecular pathways responsible for coordinating oral regen-
eration are not yet known, this implies an important role of
calcium signalling.
Although it is not well understood how the oral primordium
migrates to the anterior end of the cell during oral regeneration,
a little more is known about the placement of the new oral pri-
mordium during the early stages of regeneration. In the case of
normal cell division or oral regeneration, the new oral apparatus
begins to form in the ramifying zone, where the narrow cortical
stripes abut the wide stripes. However, it is also possible to
induce oral apparatus formation in other locations (Tartar, 1961).
In one experiment, a longitudinal fragment of the wide stripe
zone of one cell was grafted into the middle of the thin stripe
zone of a second host cell. In this case when the oral primordium
formed, one formed normally in the proper location, but two
more formed on either side of the wide stripe graft, where there
were adjacent thin stripes. In another experiment, a cell was
cut into half and the anterior half was rotated laterally 180∘and
allowed to rejoin the posterior half. In this way, the anterior
and posterior poles of the cell were still in their proper place,
but where there was wide striping on the top half, there was
thin striping on the bottom half, and vice versa. When the oral
primordium began to form, it formed longitudinally as usual
between the wide and the thin striping on both the top and the
bottom halves. However, there was also an extension of the
primordium forming a connection between these that cut across
the middle of the cell where wide striping on the anterior abutted
thin striping on the posterior. In this way, the cell developed
an oral primordium similar to an ‘S’-shape. Together, these
experiments suggest that the primordium forms wherever there
is a wide stripe adjacent to a thin stripe.
Regeneration after microsurgery
When cells are sliced in half with a glass needle, both halves are
able to fully regenerate (Figure 4). The orientation of the cut or
the size of each half does not seem to matter in the regeneration
process; indeed, the cell can even be cut into multiple pieces
and each piece will survive as long as it receives at least one
macronuclear node and possesses enough of the cortex to stretch
around the cut site. Lillie explored the lower limits on the quantity
of cytoplasm that could support full regeneration of a whole cell
and reported that fragments 1/30th the size of a normal Stentor
were able to regenerate (Lillie, 1896). Using more careful surgical
methods, Morgan subsequently found that pieces as small as
1/64th of the original cell have been able to regenerate to yield
completely normal looking cells of proper proportions (Morgan,
1901). Similar to oral regeneration after sucrose shock, a cell
fragment that has lost its oral apparatus can regenerate a new one
within 8 h, and afterwards, the cell keeps growing to regain its
previous size over a period of 24–48h. Inhibitors of transcription
or of protein synthesis prevent the completion of regeneration
(Burchill, 1968; Ellwood and Cowden, 1966), suggesting that this
process requires fresh transcription.
An anterior cell fragment needing to regenerate a holdfast can
do so much more quickly, typically within 2–3h. In contrast to
oral regeneration, regeneration of the posterior pole can even
take place in the absence of the nucleus (Tartar, 1961), indicating
that this process does not require changes in gene expression
but can be carried out by rearranging already existing proteins.
The cell appears to use its cortical striping pattern as a guide
for where to place the new holdfast, and certain microsurgical
manipulations have the ability to create a new temporary tail-pole
in an inappropriate location. If a cell is cut so that a section is
Anterior
Posterior
0 h
0 h 5 h
100 μm
2 h
8 h
8 h
(a) (b) (c)
(d) (e) (f)
Figure 4 Regeneration of anterior and posterior portions of S.coeruleus. Anterior fragments (a) are able to regenerate the holdfast rather quickly
(b) and continue to increase in size afterwards (c). Posterior fragments (d), however, need to regenerate the oral apparatus which takes much longer. Around
5 h post-surgery, the new membranellar band can be seen migrating towards the anterior pole (e), and by 8 h, the oral apparatus has fully reformed (f). The
cell will then continue to grow over the next 48 h to reach its original size. Black arrows, membranellar bands.
eLS © 2015, John Wiley & Sons, Ltd. www.els.net 5
Stentor, Its Cell Biology and Development
removed containing the original holdfast and part of the locus of
striped contrast, a new tail will form at the point where the stripes
in the locus of striped contrast were severed (Weisz, 1951). In
addition, if a cell is bisected laterally and the anterior half rotated
180∘on the posterior half, the cell’s stripes cannot rejoin, and a
new tail will form at the bottom of the anterior half on the locus
of striped contrast (Tartar, 1961). In both of these cases, the new
tails will later be resorbed as the cell realigns its striping, but
these experiments indicate that the cell uses the posterior end of
the stripes in the ramifying zone as a guide for where to place the
posterior pole of the cell.
Mob1: probing Stentor regeneration
using molecular tools
The majority of the studies on Stentor regeneration have been
based on microscopic observations after microsurgery (Tartar,
1961) or chemical inhibitor experiments (Burchill et al., 1983;
Maloney et al., 1991; Younger et al., 1972), and as a result,
there is no information about specic molecular pathways that
mediate development or regeneration in this organism. However,
new experiments are beginning to reveal details of regeneration
at the molecular and genetic level. Recently, a system for RNA
interference (RNAi) in Stentor was developed (Slabodnick et al.,
2014). RNAi is a method used by molecular biologists to silence
individual genes and has been developed as a tool for many dif-
ferent organisms, including human cells. Double-stranded RNA
(dsRNA) with sequence complementary to the target gene is
delivered to the cell, where it binds to its target mRNA. This
initiates a cellular response in which the triplex RNA, including
the target mRNA, is degraded. This degradation system occurs
naturally in many cells, including ciliates, and in nature is used by
the cell to combat dsRNA viruses. See also:RNA Interference
(RNAi) and MicroRNAs
One of the rst Stentor genes tested by RNAi was Mob1. In ani-
mals and yeast, Mob1 is known to be a kinase regulator important
for exit from mitosis (Hergovich, 2011;Lucaet al., 2001;Luca
and Winey, 1998). Knockdown of Mob1 expression in Stentor
produced cells defective in cytokinesis. These cells tried and
failed to divide and ended up with multiple tail poles and mem-
branellar bands. When healthy-looking Mob1 knockdown cells
were taken and cut in half, they attempted to regenerate but exhib-
ited abnormal morphology (Figure 5) (Slabodnick et al., 2014).
These results suggested that the Mob1 in Stentor helps maintain
polarity, and without it, cells are unable to maintain their proper
shape. In addition, because of the role of Mob1 in mitosis and
cytokinesis, these ndings reinforce the idea that several mech-
anisms involved in single cell regeneration have been co-opted
from cell division pathways. The development of RNAi methods
for Stentor now opens up molecular functional analysis of regen-
eration, development and behaviour in this fascinating model
organism.
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Mob1 (RNAi)
Control
(RNAi)
Figure 5 Knockdown of Mob1 prevents normal regeneration of cut Stentor. When control cells have their anterior and posterior ends removed
by a glass needle, the cell regenerates properly (a) but when Mob1 RNAi cells have their anterior and posterior ends removed, the cell fails to regenerate its
proper shape over time (b) (see also Slabodnick et al., 2014).
6eLS © 2015, John Wiley & Sons, Ltd. www.els.net
Stentor, Its Cell Biology and Development
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Further Reading
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Slabodnick M, Prevo B, Gross P, Sheung J and Marshall W (2013)
Visualizing cytoplasmic ow during single-cell wound healing in
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Behavioral Studies, pp. 1–59. New York: Academic Press.
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