Making waves: pattern formation by a cell-surface-associated signal

2005 ◽  
Vol 13 (6) ◽  
pp. 249-252 ◽  
Author(s):  
Angela Stevens ◽  
Lotte Søgaard-Andersen
Development ◽  
1995 ◽  
Vol 121 (9) ◽  
pp. 3045-3055 ◽  
Author(s):  
L. Zheng ◽  
J. Zhang ◽  
R.W. Carthew

Coordinated morphogenesis of ommatidia during Drosophila eye development establishes a mirror-image symmetric pattern across the entire eye bisected by an anteroposterior equator. We have investigated the mechanisms by which this pattern formation occurs and our results suggest that morphogenesis is coordinated by a graded signal transmitted bidirectionally from the presumptive equator to the dorsal and ventral poles. This signal is mediated by frizzled, which encodes a cell surface transmembrane protein. Mosaic analysis indicates that frizzled acts non-autonomously in an equatorial to polar direction. It also indicates that relative levels of frizzled in photoreceptor cells R3 and R4 of each ommatidium affect their positional fate choices such that the cell with greater frizzled activity becomes an R3 cell and the cell with less frizzled activity becomes an R4 cell. Moreover, this bias affects the choice an ommatidium makes as to which direction to rotate. Equator-outwards progression of elav expression and expression of the nemo gene in the morphogenetic furrow are regulated by frizzled, which itself is dynamically expressed about the morphogenetic furrow. We propose that frizzled mediates a bidirectional signal emanating from the equator.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jonas Mattisson ◽  
Marcus Danielsson ◽  
Maria Hammond ◽  
Hanna Davies ◽  
Caroline J. Gallant ◽  
...  

AbstractMosaic loss of chromosome Y (LOY) in immune cells is a male-specific mutation associated with increased risk for morbidity and mortality. The CD99 gene, positioned in the pseudoautosomal regions of chromosomes X and Y, encodes a cell surface protein essential for several key properties of leukocytes and immune system functions. Here we used CITE-seq for simultaneous quantification of CD99 derived mRNA and cell surface CD99 protein abundance in relation to LOY in single cells. The abundance of CD99 molecules was lower on the surfaces of LOY cells compared with cells without this aneuploidy in all six types of leukocytes studied, while the abundance of CD proteins encoded by genes located on autosomal chromosomes were independent from LOY. These results connect LOY in single cells with immune related cellular properties at the protein level, providing mechanistic insight regarding disease vulnerability in men affected with mosaic chromosome Y loss in blood leukocytes.


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