TY - JOUR
T1 - Photoreceptor cell differentiation requires regulated proteolysis of the transcriptional repressor Tramtrack
AU - Li, Songhui
AU - Li, Ying
AU - Carthew, Richard W.
AU - Lai, Zhi Chun
N1 - Funding Information:
Correspondence regarding this paper should be addressed to R. W. C. ([email protected]) or Z.-C. L. ([email protected]). We wish to thank C. Klambt and M. Freeman for their generous gift of fly stocks; K. Arndt, M. Kuziora, and S. Harrison for their gift of plasmids; D. Read and S. Harrison for antibodies; P. Gallagher and L. Crowell for technical help; and J. Brodsky for advice. This work was supported by funds provided to R. W. C. from the National Institutes of Health (EY10111), and the March of Dimes Foundation (Basic Research) and to Z.-C. L. from the National Science Foundation (IBN9511201). R. W. C. is a Pew Scholar in the Biomedical Sciences. Z.-C. L. is a recipient of a March of Dimes Basil O'Connor Starter Scholar Research Award.
PY - 1997/8/8
Y1 - 1997/8/8
N2 - The transcription repressor Tramtrack (TTK) is found in cone cells but not photoreceptor cells of the Drosophila eye. We show that down-regulation of TTK expression occurs in photoreceptor cells and is required for their fate determination. Down-regulation requires the presence of Phyllopod (PHYL), which is induced by the RAS pathway, and Seven In Absentia (SINA). Loss of either gene causes accumulation of TTK in photoreceptor cells, and TTK does not accumulate in cone cells if both PHYL and SINA are present. We report that SINA and PHYL promote ubiquitination and rapid degradation of TTK by the proteasome pathway in cell culture, and both SINA and PHYL bind to the N-terminal domain of TTK. These results argue that photoreceptor differentiation is regulated by the RAS pathway through targeted proteolysis of the TTK repressor.
AB - The transcription repressor Tramtrack (TTK) is found in cone cells but not photoreceptor cells of the Drosophila eye. We show that down-regulation of TTK expression occurs in photoreceptor cells and is required for their fate determination. Down-regulation requires the presence of Phyllopod (PHYL), which is induced by the RAS pathway, and Seven In Absentia (SINA). Loss of either gene causes accumulation of TTK in photoreceptor cells, and TTK does not accumulate in cone cells if both PHYL and SINA are present. We report that SINA and PHYL promote ubiquitination and rapid degradation of TTK by the proteasome pathway in cell culture, and both SINA and PHYL bind to the N-terminal domain of TTK. These results argue that photoreceptor differentiation is regulated by the RAS pathway through targeted proteolysis of the TTK repressor.
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U2 - 10.1016/S0092-8674(00)80507-3
DO - 10.1016/S0092-8674(00)80507-3
M3 - Article
C2 - 9267027
AN - SCOPUS:0030790796
SN - 0092-8674
VL - 90
SP - 469
EP - 478
JO - Cell
JF - Cell
IS - 3
ER -