Abdominal-A mediated repression of Cyclin E expression during cell-fate specification in the Drosophila central nervous system.
Homeotic/Hox genes are known to specify a given developmental pathway by regulating the expression of downstream effector genes. During embryonic CNS development of Drosophila, the Hox protein Abdominal-A (AbdA) is required for the specification of the abdominal NB6-4 lineage. It does so by down regulating the expression of the cell cycle regulator gene Dcyclin E (CycE). CycE is normally expressed in the thoracic NB6-4 lineage to give rise to mixed lineage of neurons and glia, while only glial cells are produced from the abdominal NB6-4 lineage due to the repression of CycE by AbdA. Here we investigate how AbdA represses the expression of CycE to define the abdominal fate of a single NB6-4 precursor cell. We analyze, both in vitro and in vivo, the regulation of a 1.9 kb CNS-specific CycE enhancer element in the abdominal NB6-4 lineage. We show that CycE is a direct target of AbdA and it binds to the CNS specific enhancer of CycE to specifically repress the enhancer activity in vivo. Our results suggest preferential involvement of a series of multiple AbdA binding sites to selectively enhance the repression of CycE transcription. Furthermore, our data suggest a complex network to regulate CycE expression where AbdA functions as a key regulator.
Center for Cellular and Molecular Biology, Hyderabad, India.
Ramakrishnan
R
Kannan
Christian
C
Berger
Sudharani
S
Myneni
Gerhard M
GM
Technau
L S
LS
Shashidhara
D000818:Animals; D030801:Animals, Genetically Modified; D002454:Cell Differentiation / Q000235:genetics; D019070:Cell Lineage; D002490:Central Nervous System / Q000196:embryology*; D019927:Cyclin E / Q000037:antagonists & inhibitors / Q000502:physiology*; D004331:Drosophila melanogaster / Q000196:embryology*; D018507:Gene Expression Regulation, Developmental; D018398:Homeodomain Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism / Q000502:physiology*; D017403:In Situ Hybridization; D009457:Neuroglia / Q000378:metabolism; D009474:Neurons / Q000378:metabolism; D014158:Transcription, Genetic; D019076:Transgenes
C410542:Abd-A protein, insect; D019927:Cyclin E; D018398:Homeodomain Proteins