A novel proneural function of Asense is integrated with the sequential actions of Delta-Notch, L'sc and Su(H) to promote the neuroepithelial to neuroblast transition.

"reviewer #1: no reviewer #2: yes: michel gho reviewer #3: no ---------------------------------------------------- data deposition if you have submitted a research article or front matter that has associated data that are not suitable for deposition in a subject-specific public repository (such as genbank or arrayexpress) one way to make that data available is to deposit it in the dryad digital repository .; journalid=pgenetics&manu=pgenetics-d-23-00385r1 more information about depositing data in dryad is available at http://www datadryad org/depositing . we found that mira (nb marker) and decad (ne marker) were co-expressed in many cells during the ne-nb transition ( fig 2a 2b and 2i ; s1 data ) and that many l'sc + cells were located more towards the middle of the ne rather than at its edge as it happens in wt brains ( fig 2a and 2b ; 9/9 brains).; furthermore all the ase + cells at the surface of the opc had weak ase labeling and co-expressed mira ( fig 2e-2h ; s3a-s3c fig ; s1 data ).; remarkably these ase-rnai conditions caused the same phenotype as the ase 1 mutation with a significant increase in the number of cells co-expressing ne and nb markers ( fig 2e-2i ; s3a s3b s3d fig ; s1 data ).; interestingly this misexpression produced ectopic cells expressing nb markers (dpn and mira) within the ne and at its edge ( fig 3c and 3d ; s3a fig ; s1 data ; table 1 ).; furthermore a short (8h) induction of l'sc in the ne which reached similar (or higher) levels as the endogenous expression in transition cells ( s2e fig ; s1 data ) did not trigger nb marker expression in the medulla ne ( fig 4a and 4c ; s4e-s4h fig ; table 1 ) although we detected induction of mira in the lamina ne ( s4e-s4h fig ).; furthermore the induction of dl-dn in the ne for a short period was sufficient to substantially reduce the number of peak of ase cells ( s5e fig ; s1 data ).; this possibility is also supported by the observation that the down-regulation of notch with dl-dn appears to repress ase expression ( fig 4d and 4e ; s5c-s5e fig s1 data ).; conversely the downregulation of notch in nbs with dl-dn driven by ase-gal 4 in medulla nbs produced an increase in ase labeling intensity compared to control nbs ( fig 5l-5n : s1 data 6/6 brains).; consistent with this expression pattern and su(h) being a repressor of ase expressing su(h) in ne and transitioning cells under the c820-gal4 driver caused a widespread reduction of ase expression and a fall in the number of peak of ase cells ( fig 7a-7c ; 10/10 brains; s1 data ).; notice that there are not additional l'sc+ cells in the c855a-gal4>-dl-dn sample compared to the control (pdf) click here for additional data file s1 data excel file containing the numerical data and summary statistics used to generate the graphs displayed in the corresponding figures."

"The authors have declared that no competing interests exist."

"This work was supported by grants from the Ministerio de Economía, Industria y Competitividad (AEI/FEDER, UE: BFU2016–80273-R) and CSIC (2020AEP180) to FJT. MNS was recipient of a Santiago Grisolia Fellowship from the Generalitat Valenciana. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript."