0000000000548677
AUTHOR
L. S. Shashidhara
A critical role for Cyclin E in cell fate determination in the central nervous system of Drosophila melanogaster
We have examined the process by which cell diversity is generated in neuroblast (NB) lineages in the central nervous system of Drosophila melanogaster. Thoracic NB6-4 (NB6-4t) generates both neurons and glial cells, whereas NB6-4a generates only glial cells in abdominal segments. This is attributed to an asymmetric first division of NB6-4t, localizing prospero (pros) and glial cell missing (gcm) only to the glial precursor cell, and a symmetric division of NB6-4a, where both daughter cells express pros and gcm. Here we show that the NB6-4t lineage represents the ground state, which does not require the input of any homeotic gene, whereas the NB6-4a lineage is specified by the homeotic genes…
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 …
Cyclin E acts under the control of Hox-genes as a cell fate determinant in the developing central nervous system.
The mechanisms controlling the generation of cell diversity in the central nervous system belong to the major unsolved problems in developmental biology. The fly Drosophila melanogaster is a suitable model system to examine these mechanisms at the level of individually identifiable cells. Recently, we have provided evidence that CyclinE--largely independent of its role in cell proliferation--plays a critical role in the specification of neural stem cells (neuroblasts). CycE specifies neuronal fate within neuroblast lineages by acting upstream of glial factors (prospero and glial cell missing), whereby levels of CycE are controlled by homeotic genes, the master control genes regulating segme…
Cell cycle independent role of Cyclin E during neural cell fate specification in Drosophila is mediated by its regulation of Prospero function
AbstractDuring development, neural progenitor cells or neuroblasts generate a great intra- and inter-segmental diversity of neuronal and glial cell types in the nervous system. In thoracic segments of the embryonic central nervous system of Drosophila, the neuroblast NB6-4t undergoes an asymmetric first division to generate a neuronal and a glial sublineage, while abdominal NB6-4a divides once symmetrically to generate only 2 glial cells. We had earlier reported a critical function for the G1 cyclin, CyclinE (CycE) in regulating asymmetric cell division in NB6-4t. Here we show that (i) this function of CycE is independent of its role in cell cycle regulation and (ii) the two functions are m…