Biology subjects

Lawrence, P. A.

Publications and source records attributed to Lawrence, P. A..

3 recordsLinked to original sources

bioRxiv2022

Planar cell polarity: intracellular asymmetry and supracellular gradients of Dachsous

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: 1. A supracellular gradient that rises from head to tail in the anterior compartment (A) and then falls in the posterior compartment (P). 2. There is more Ds in the front than the rear membranes of all cells in the A compartment, except that compartments 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 3. 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.

developmental biology↗

bioRxiv2018

A refutation to ‘A new A-P compartment boundary and organizer in holometabolous insect wings.’

We respond to a recent report by Abbasi and Marcus who present two main findings: first they argue that there is an organiser and a compartment boundary within the posterior compartment of the butterfly wing. Second, they present evidence for a previously undiscovered lineage boundary near wing vein 5 in Drosophila, a boundary that delineates a \"far posterior\" compartment. Clones of cells were marked with the yellow mutation and they reported that these clones always fail to cross a line close to vein 5 on the Drosophila wing. In our hands yellow proved an unusable marker for clones in the wing blade and therefore we reexamined the matter. We marked clones of cells with multiple wing hairs or forked and found a substantial proportion of these clones cross the proposed lineage boundary near vein 5, in conflict with their findings and conclusion. As internal controls we showed that these same clones respect the other two well established compartment boundaries: the anteroposterior compartment boundary is always respected. The dorsoventral boundary is mostly respected, and is crossed only by clones that are induced early in development, consistent with many reports. We question the validity of Abbasi and Marcus conclusions regarding the butterfly wing but present no new data.\n\nArising from: R. Abbasi and J. M. Marcus Sci. Rep. 7, 16337 (2017); https://doi.org/10.1038/s41598-017-16553-5

developmental biology↗

bioRxiv2017

Planar Cell Polarity: What Does The prickle Gene Do?

Epithelial cells are polarised within the plane of the epithelium, forming oriented structures whose coordinated and consistent polarity (planar cell polarity, PCP) relates to the principal axes of the body or organ. In Drosophila at least two separate molecular systems generate and interpret intercellular polarity signals: Dachsous/Fat, and the \"core\" or Stan system. Here we study the prickle gene and its protein products Prickle and Spiny leg. Much research on PCP has focused on the asymmetric localisation of core proteins in the cell and as a result prickle was placed in the heart of the Stan system. Here we ask if this view is correct and how the prickle gene relates to the two systems. We find that prickle can affect, separately, both systems -- however, neither Pk nor Sple are essential components of the Ds/Ft or the Stan system, nor do they act as a functional link between the two systems.

developmental biology↗