TY - JOUR
T1 - Identification of a novel transcriptional activity of mammalian Id proteins
AU - Bounpheng, Mangkey A.
AU - Melnikova, Irena N.
AU - Dimas, Joseph J.
AU - Christy, Barbara A.
N1 - Funding Information:
We thank Drs Wen-Hwa Lee, Daniel Nathans, Richard Baer, Toomas Neuman, Stephen Skapek, Robert Christy, Steve McKnight, Ed Seto and Ed Ziff for materials, and Sherry Dodds for technical assistance. We are grateful to Drs Gokul Das, Gina Schatteman and Wen-Ming Yang for critical reading of the manuscript. This work was supported by grant R29HD29850 from the National Institutes of Health, grant 1-FY96-0126 from the March of Dimes Birth Defects Foundation and grant 98G-345 from the American Heart Association, Texas Affiliate.
PY - 1999/4/1
Y1 - 1999/4/1
N2 - The Id proteins are a family of related mammalian helix-loop-helix (HLH) proteins which can interact with other HLH proteins but lack a basic region and are thus not thought to bind to DNA. Instead, they are hypothesized to act as dominant negative regulators of DNA-binding basic HLH (bHLH) proteins, by forming inactive heterodimers with these proteins. All four Id family proteins possess related HLH dimerization domains and can interact with similar bHLH proteins, although with differing affinities. The functions of the largely unrelated N- and C-terminal regions of the proteins are unknown. In this study, we have identified a novel transcriptional activity of the mammalian Id proteins. We show that when fused to the heterologous GAL4 DNA-binding domain, all four of the mammalian Id proteins can activate GAL4-dependent transcription. The HLH domain is necessary for the transactivation activity observed, suggesting that interaction with a cellular HLH protein is required. Co-transfection with exogenous Class A bHLH proteins (E-proteins) greatly potentiates the transactivation, which is abolished upon co-transfection with Class B bHLH proteins. These results are consistent with the idea that the Id proteins have a transcriptional activity when present in a DNA-binding complex.
AB - The Id proteins are a family of related mammalian helix-loop-helix (HLH) proteins which can interact with other HLH proteins but lack a basic region and are thus not thought to bind to DNA. Instead, they are hypothesized to act as dominant negative regulators of DNA-binding basic HLH (bHLH) proteins, by forming inactive heterodimers with these proteins. All four Id family proteins possess related HLH dimerization domains and can interact with similar bHLH proteins, although with differing affinities. The functions of the largely unrelated N- and C-terminal regions of the proteins are unknown. In this study, we have identified a novel transcriptional activity of the mammalian Id proteins. We show that when fused to the heterologous GAL4 DNA-binding domain, all four of the mammalian Id proteins can activate GAL4-dependent transcription. The HLH domain is necessary for the transactivation activity observed, suggesting that interaction with a cellular HLH protein is required. Co-transfection with exogenous Class A bHLH proteins (E-proteins) greatly potentiates the transactivation, which is abolished upon co-transfection with Class B bHLH proteins. These results are consistent with the idea that the Id proteins have a transcriptional activity when present in a DNA-binding complex.
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U2 - 10.1093/nar/27.7.1740
DO - 10.1093/nar/27.7.1740
M3 - Article
C2 - 10076006
AN - SCOPUS:0033118264
VL - 27
SP - 1740
EP - 1746
JO - Nucleic Acids Research
JF - Nucleic Acids Research
SN - 0305-1048
IS - 7
ER -