
==== Front
bioRxiv
BIORXIV
bioRxiv
2692-8205
Cold Spring Harbor Laboratory

10.1101/2024.09.04.611161
preprint
1
Article
The Hox Gene, abdominal A controls timely mitotic entry of neural stem cell and their growth during CNS development in Drosophila
Das Papri
Murthy Smrithi
Abbas Eshan
White Kristin
Arya Richa http://orcid.org/0000-0003-4464-699X

05 9 2024
2024.09.04.611161https://creativecommons.org/licenses/by-nc-nd/4.0/ This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, which allows reusers to copy and distribute the material in any medium or format in unadapted form only, for noncommercial purposes only, and only so long as attribution is given to the creator.
http://biorxiv.org/lookup/doi/10.1101/2024.09.04.611161
nihpp-2024.09.04.611161.pdf
Abstract

The size of a cell is important for its function and physiology. Interestingly, size variation can be easily observed in clonally derived embryonic and hematopoietic stem cells. Here, we investigated the regulation of stem cell growth and its association with cell fate. We observed heterogeneous sizes of neuroblasts or neural stem cells (NSCs) in the Drosophila ventral nerve cord (VNC). Specifically, thoracic NSCs were larger than those in the abdominal region of the VNC. Our research uncovered a significant role of the Hox gene abdominal A ( abdA ) in the regulation of abdominal NSC growth. Developmental expression of AbdA retards their growth and delays mitotic entry compared to thoracic NSCs. The targeted loss of abdA enhanced their growth and caused an earlier entry into mitosis with a faster cycling rate. Furthermore, ectopic expression of abdA reduced the size of thoracic NSCs and delayed their entry into mitosis. We suggest that abdA plays an instructive role in regulating NSC size and exit from quiescence. This study demonstrates for the first time the involvement of abdA in NSC fate determination by regulating their growth, entry into mitosis and proliferation rate, and thus their potential to make appropriate number of progeny for CNS patterning.

Significance statement

Understanding the upstream regulation of various aspects of the cell cycle is very important, how cell growth influences the process is largely unknown.

We found an instructive role of the Hox gene abdominal A in maintaining the small size of neural stem cells (NSCs) and limiting their ability to undergo mitosis.

This mechanism is crucial, as it helps NSCs generate the necessary number of neurons at the appropriate developmental stage, thereby contributing to proper central nervous system patterning.
==== Body
pmc
