Abstract:We investigate planar cell polarity (PCP) in the
Drosophila
larval epidermis. The intricate pattern of denticles depends on only one system of PCP, the Dachsous/Fat system. Dachsous molecules in one cell bind to Fat molecules in a neighbour cell to make intercellular bridges. The disposition and orientation of these Dachsous–Fat bridges allows each cell to compare two neighbours and point its denticles towards the neighbour with the most Dachsous. Measurements of the amount of Dachsous … Show more
“…Ft-Ds may also regulate microtubule orientation and core protein polarity in the anterior compartment of the abdomen. Here, microtubule plus-end growth is weakly biased towards the posterior ends of cells [54], although predominantly growth is along the mediolateral axis of the abdomen, orthogonal to the axis of asymmetry [129]. Consistent with this slight plus-end bias, Dsh particles show a posterior bias in their transport, as expected from the axis of the polarity of royalsocietypublishing.org/journal/rsob Open Biol.…”
Section: Regulation Of Microtubule Orientation By Ft and Dssupporting
confidence: 66%
“…The core proteins localize asymmetrically to anterior-posterior cell edges, but loss of core protein activity has relatively little effect on denticle orientation [107,[134][135][136]. However, in the embryo and larva, denticle polarity correlates with asymmetric localization of Ds and D [129,137,138], and loss or overexpression of Ft-Ds severely disrupts denticle belt polarity [107,[136][137][138][139]. Fj is highly expressed in the tendon cells which are posterior to rows 1 and 4 in the larval epidermis, which may explain the pattern of denticle polarity [140].…”
Section: Polarization Of Cuticular Structures Bymentioning
confidence: 99%
“…11: 200356 One way in which Ft and Ds might influence the polarization of cuticular structures could be by regulating cell shape and alignment. In wild-type embryos, cells are elongated on the dorsoventral axis and microtubules are aligned on this long axis [129,138]. In the absence of Ft, cells fail to elongate on the dorsoventral axis, and microtubules are disorganized [138].…”
Section: Polarization Of Cuticular Structures Bymentioning
Planar polarity describes the coordinated polarization of cells within the plane of a tissue. This is controlled by two main pathways in
Drosophila
: the Frizzled-dependent core planar polarity pathway and the Fat–Dachsous pathway. Components of both of these pathways become asymmetrically localized within cells in response to long-range upstream cues, and form intercellular complexes that link polarity between neighbouring cells. This review examines if and when the two pathways are coupled, focusing on the
Drosophila
wing, eye and abdomen. There is strong evidence that the pathways are molecularly coupled in tissues that express a specific isoform of the core protein Prickle, namely Spiny-legs. However, in other contexts, the linkages between the pathways are indirect. We discuss how the two pathways act together and independently to mediate a diverse range of effects on polarization of cell structures and behaviours.
“…Ft-Ds may also regulate microtubule orientation and core protein polarity in the anterior compartment of the abdomen. Here, microtubule plus-end growth is weakly biased towards the posterior ends of cells [54], although predominantly growth is along the mediolateral axis of the abdomen, orthogonal to the axis of asymmetry [129]. Consistent with this slight plus-end bias, Dsh particles show a posterior bias in their transport, as expected from the axis of the polarity of royalsocietypublishing.org/journal/rsob Open Biol.…”
Section: Regulation Of Microtubule Orientation By Ft and Dssupporting
confidence: 66%
“…The core proteins localize asymmetrically to anterior-posterior cell edges, but loss of core protein activity has relatively little effect on denticle orientation [107,[134][135][136]. However, in the embryo and larva, denticle polarity correlates with asymmetric localization of Ds and D [129,137,138], and loss or overexpression of Ft-Ds severely disrupts denticle belt polarity [107,[136][137][138][139]. Fj is highly expressed in the tendon cells which are posterior to rows 1 and 4 in the larval epidermis, which may explain the pattern of denticle polarity [140].…”
Section: Polarization Of Cuticular Structures Bymentioning
confidence: 99%
“…11: 200356 One way in which Ft and Ds might influence the polarization of cuticular structures could be by regulating cell shape and alignment. In wild-type embryos, cells are elongated on the dorsoventral axis and microtubules are aligned on this long axis [129,138]. In the absence of Ft, cells fail to elongate on the dorsoventral axis, and microtubules are disorganized [138].…”
Section: Polarization Of Cuticular Structures Bymentioning
Planar polarity describes the coordinated polarization of cells within the plane of a tissue. This is controlled by two main pathways in
Drosophila
: the Frizzled-dependent core planar polarity pathway and the Fat–Dachsous pathway. Components of both of these pathways become asymmetrically localized within cells in response to long-range upstream cues, and form intercellular complexes that link polarity between neighbouring cells. This review examines if and when the two pathways are coupled, focusing on the
Drosophila
wing, eye and abdomen. There is strong evidence that the pathways are molecularly coupled in tissues that express a specific isoform of the core protein Prickle, namely Spiny-legs. However, in other contexts, the linkages between the pathways are indirect. We discuss how the two pathways act together and independently to mediate a diverse range of effects on polarization of cell structures and behaviours.
“…Within the A compartment, about two rows of the most anterior cells (figure 5 c ) and about two rows of the most posterior cells (figure 5 d ) show D located posteriorly; thus, their Ds/Ft polarity is that normally characteristic of the P cells. The third instar larva, having fewer but larger polyploid cells told a similar story: a set of cells in the A compartment, those confined to the extreme posterior row, had variable polarity with some showing the same polarity as in the P compartment (D accumulating posteriorly, [40]). Figure 5Asymmetric localization of Dachs vis-à-vis A/P boundary.…”
The slope of a supracellular molecular gradient has long been thought to orient and coordinate planar cell polarity (PCP). Here we demonstrate and measure that gradient. Dachsous (Ds) is a conserved and elemental molecule of PCP; Ds forms intercellular bridges with another cadherin molecule, Fat (Ft), an interaction modulated by the Golgi protein Four-jointed (Fj). Using genetic mosaics and tagged Ds, we measure Ds
in vivo
in membranes of individual cells over a whole metamere of the
Drosophila
abdomen. We find as follows. (i) A supracellular gradient rises from head to tail in the anterior compartment (A) and then falls in the posterior compartment (P). (ii) There is more Ds in the front than the rear membranes of all cells in the A compartment, except that compartment's most anterior and most posterior cells. There is more Ds in the rear than in the front membranes of all cells of the P compartment. (iii) The loss of Fj removes intracellular asymmetry anteriorly in the segment and reduces it elsewhere. Additional experiments show that Fj makes PCP more robust. Using Dachs (D) as a molecular indicator of polarity, we confirm that opposing gradients of PCP meet slightly out of register with compartment boundaries.
“…However and even so, there was an attractive hypothesis as to how the Ds/Ft and Stan/Fz systems might be linked: it was suggested that microtubules could be oriented by Ds/Ft and thereby polarize the intracellular transport of molecules such as Fz [ 32 , 33 ]. But some key published data were questioned when reexamined and the model challenged by new observations on microtubules in polarized larval and adult abdominal cells [ 34 ]. Microtubule organization is nevertheless related to cell shape in several different kinds of epidermis [ 34 , 35 ].…”
Planar cell polarity (PCP), the coordinated orientation of structures such as cilia, mammalian hairs or insect bristles, depends on at least two molecular systems. We have argued that these two systems use similar mechanisms; each depending on a supracellular gradient of concentration that spans a field of cells. In a linked paper, we studied the Dachsous/Fat system. We found a graded distribution of Dachsous
in vivo
in a segment of the pupal epidermis in the abdomen of
Drosophila
. Here we report a similar study of the key molecule for the Starry Night/Frizzled or ‘core’ system. We measure the distribution of the receptor Frizzled on the cell membranes of all cells of one segment in the living pupal abdomen of
Drosophila
. We find a supracellular gradient that falls about 17% in concentration from the front to the rear of the segment. We present some evidence that the gradient then resets in the most anterior cells of the next segment back. We find an intracellular asymmetry in all the cells, the posterior membrane of each cell carrying about 22% more Frizzled than the anterior membrane. These direct molecular measurements add to earlier evidence that the two systems of PCP act independently.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
