TY - JOUR
T1 - E2A basic-helix-loop-helix transcription factors are negatively regulated by serum growth factors and by the Id3 protein
AU - Loveys, Deborah A.
AU - Streiff, Michael B.
AU - Kato, Gregory J.
N1 - Funding Information:
We gratefully acknowledge the support and contributions of Daniel Nathans, in whose lab these studies were initiated. We thank Laura Sanders for technical assistance, John Williams for a blot of RNA samples, and Timothy Schaefer, Pierre Chevray, Lian Fong and Chi Dang for their thoughts and advice. G.J.K. has been supported by Public Health Service grants CA01622 from the National Cancer Institute and HD27799 from the National Heart, Lung, and Blood Institute, and by the Parker Hughes Trust. M.B.S. is an ASCO Young Investigator, and is supported by Public Health Service grant HL07525 from the National Heart, Lung and Blood Institute. D.A.L. is supported by Public Health Service grant CA60441 from the National Cancer Institute.
PY - 1996
Y1 - 1996
N2 - Id3, a member of the Id multigene family of dominant negative helix-loop-helix transcription factors, is induced sharply in murine fibroblasts by serum growth factors. To identify relevant targets of Id3 activity, the yeast two-hybrid system was used to identify proteins that dimerize with Id3. Four murine cDNAs were identified in the screen, all of which encode helix-loop helix proteins: E12, E47, ALF1 and Id4. Co-immunoprecipitation assays confirm that Id3 interacts with E12, E47 and two alternative splice products of ALF1 in vitro. Id3 disrupts DNA binding by these proteins in vitro and blocks transcriptional activation by these factors in cultured murine cells. Additionally, Id3 shows evidence of interacting with the related proteins E2-2 and MyoD, but not c-Myc. These results suggest that Id3 can function as a general negative regulator of the basic-helix-loop-helix family of transcription factors exemplified by the 'E' proteins and MyoD. Although it was previously suspected that E2A is constitutively expressed, our data indicate that E2A is induced in quiescent fibroblasts, by growth factor withdrawal but not by contact inhibition of cell proliferation. These observations extend the role of Id3 in the functional antagonism of E2A-class transcription factors, and suggest that E2A proteins may mediate growth inhibition.
AB - Id3, a member of the Id multigene family of dominant negative helix-loop-helix transcription factors, is induced sharply in murine fibroblasts by serum growth factors. To identify relevant targets of Id3 activity, the yeast two-hybrid system was used to identify proteins that dimerize with Id3. Four murine cDNAs were identified in the screen, all of which encode helix-loop helix proteins: E12, E47, ALF1 and Id4. Co-immunoprecipitation assays confirm that Id3 interacts with E12, E47 and two alternative splice products of ALF1 in vitro. Id3 disrupts DNA binding by these proteins in vitro and blocks transcriptional activation by these factors in cultured murine cells. Additionally, Id3 shows evidence of interacting with the related proteins E2-2 and MyoD, but not c-Myc. These results suggest that Id3 can function as a general negative regulator of the basic-helix-loop-helix family of transcription factors exemplified by the 'E' proteins and MyoD. Although it was previously suspected that E2A is constitutively expressed, our data indicate that E2A is induced in quiescent fibroblasts, by growth factor withdrawal but not by contact inhibition of cell proliferation. These observations extend the role of Id3 in the functional antagonism of E2A-class transcription factors, and suggest that E2A proteins may mediate growth inhibition.
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U2 - 10.1093/nar/24.14.2813
DO - 10.1093/nar/24.14.2813
M3 - Article
C2 - 8759016
AN - SCOPUS:0029898630
SN - 1362-4962
VL - 24
SP - 2813
EP - 2820
JO - Nucleic Acids Research
JF - Nucleic Acids Research
IS - 14
ER -