@article {1459,
	title = {Sequential activation of Notch and~Grainyhead~gives apoptotic competence to Abdominal-B expressing larval neuroblasts in Drosophila Central nervous system [Transgenic Fly Facility]},
	journal = {PLoS Genet},
	volume = {16},
	year = {2020},
	month = {2020 Aug 31},
	pages = {e1008976},
	abstract = {<p>Neural circuitry for mating and reproduction resides within the terminal segments of central nervous system (CNS) which express Hox paralogous group 9-13 (in vertebrates) or Abdominal-B (Abd-B) in Drosophila. Terminal neuroblasts (NBs) in A8-A10 segments of Drosophila larval CNS are subdivided into two groups based on expression of transcription factor Doublesex (Dsx). While the sex specific fate of Dsx-positive NBs is well investigated, the fate of Dsx-negative NBs is not known so far. Our studies with Dsx-negative NBs suggests that these cells, like their abdominal counterparts (in A3-A7 segments) use Hox, Grainyhead (Grh) and Notch to undergo cell death during larval development. This cell death also happens by transcriptionally activating RHG family of apoptotic genes through a common apoptotic enhancer in early to mid L3 stages. However, unlike abdominal NBs (in A3-A7 segments) which use resident Hox gene Abdominal-A (Abd-A) as an apoptosis trigger, Dsx-negative NBs (in A8-A10 segments) keep the levels of resident Hox gene Abd-B constant. These cells instead utilize increasing levels of the temporal transcription factor Grh and a rise in Notch activity to gain apoptotic competence. Biochemical and in vivo analysis suggest that Abdominal-A and Grh binding motifs in the common apoptotic enhancer also function as Abdominal-B and Grh binding motifs and maintains the enhancer activity in A8-A10 NBs. Finally, the deletion of this enhancer by the CRISPR-Cas9 method blocks the apoptosis of Dsx-negative NBs. These results highlight the fact that Hox dependent NB apoptosis in abdominal and terminal regions utilizes common molecular players (Hox, Grh and Notch), but seems to have evolved different molecular strategies to pattern CNS.</p>
},
	issn = {1553-7404},
	doi = {10.1371/journal.pgen.1008976},
	author = {Bakshi, Asif and Sipani, Rashmi and Ghosh, Neha and Joshi, Rohit}
}
@article {683,
	title = {Combinatorial action of Grainyhead, Extradenticle and Notch in regulating Hox mediated apoptosis in Drosophila larval CNS.},
	journal = {PLoS Genet},
	volume = {13},
	year = {2017},
	month = {2017 Oct},
	pages = {e1007043},
	abstract = {<p>Hox mediated neuroblast apoptosis is a prevalent way to pattern larval central nervous system (CNS) by different Hox genes, but the mechanism of this apoptosis is not understood. Our studies with Abdominal-A (Abd-A) mediated larval neuroblast (pNB) apoptosis suggests that AbdA, its cofactor Extradenticle (Exd), a helix-loop-helix transcription factor Grainyhead (Grh), and Notch signaling transcriptionally contribute to expression of RHG family of apoptotic genes. We find that Grh, AbdA, and Exd function together at multiple motifs on the apoptotic enhancer. In vivo mutagenesis of these motifs suggest that they are important for the maintenance of the activity of the enhancer rather than its initiation. We also find that Exd function is independent of its known partner homothorax in this apoptosis. We extend some of our findings to Deformed expressing region of sub-esophageal ganglia where pNBs undergo a similar Hox dependent apoptosis. We propose a mechanism where common players like Exd-Grh-Notch work with different Hox genes through region specific enhancers to pattern respective segments of larval central nervous system.</p>
},
	keywords = {Amino Acid Sequence, Animals, Apoptosis, Central Nervous System, DNA-Binding Proteins, Drosophila, Drosophila Proteins, Enhancer Elements, Genetic, Female, Gene Expression Regulation, Developmental, Genes, Homeobox, Homeodomain Proteins, Larva, Male, Nuclear Proteins, Receptors, Notch, Transcription Factors},
	issn = {1553-7404},
	doi = {10.1371/journal.pgen.1007043},
	author = {Khandelwal, Risha and Sipani, Rashmi and Govinda Rajan, Sriivatsan and Kumar, Raviranjan and Joshi, Rohit}
}
