Editing Notch signaling pathway (section)

=== Photoreceptor development ===
In ''Drosophila'' eye development, photoreceptors undergo two waves of differentiation, where five out of eight photoreceptors differentiate in the first wave (R8, R2, R5, R3, and R4), and the other three differentiate in the second wave (R1, R6, and R7).<ref>{{Cite journal |last=Treisman |first=Jessica E. |date=July 2013 |title=Retinal differentiation in Drosophila |journal=WIREs Developmental Biology |language=en |volume=2 |issue=4 |pages=545–557 |doi=10.1002/wdev.100 |issn=1759-7684 |pmc=3909661 |pmid=24014422}}</ref> Notch has been shown to promote the second mitotic wave in ''Drosophila'' eye development.<ref name=":1">{{Cite journal |last1=Baonza |first1=Antonio |last2=Freeman |first2=Matthew |date=2005-04-01 |title=Control of Cell Proliferation in the Drosophila Eye by Notch Signaling |url=https://linkinghub.elsevier.com/retrieve/pii/S1534580705000237 |journal=Developmental Cell |language=English |volume=8 |issue=4 |pages=529–539 |doi=10.1016/j.devcel.2005.01.019 |issn=1534-5807 |pmid=15809035}}</ref> Specifically, it mediates the G1/S transition by promoting dE2F activation (''Drosophila'' E2F), a member of the [[E2F]] transcription factor family, which regulates the expression of genes important for cell proliferation, specifically those involved in the G1/S transition.<ref name=":1" /><ref>{{Cite journal |last1=Johnson |first1=David G. |last2=Schneider-Broussard |first2=Robin |date=1998-04-27 |title=Role of E2F in cell cycle control and cancer |url=https://www.imrpress.com/journal/FBL/3/4/10.2741/A291 |journal=Frontiers in Bioscience (Landmark Edition) |volume=3 |issue=4 |pages=447–458 |doi=10.2741/A291 |pmid=9556498 |issn=2768-6701}}</ref> Notch does this by inhibiting RBF1 (the ''Drosophila'' homolog of the tumor suppressor [[Retinoblastoma protein|Rb]]), which represses dE2F.<ref name=":1" /> Additionally, Notch is required for [[cyclin A]] activation, which accumulates during the G1/S transition and may be involved in S phase onset.<ref name=":1" />