The polymyositis-scleroderma autoantigen interacts with the helix-loop-helix proteins E12 and E47.
The basic helix-loop-helix (bHLH) transcription factors E12 and E47 regulate cellular differentiation and proliferation in diverse cell types. While looking for proteins that bind to E12 and E47 by the yeast interaction trap, we isolated the rat (r) homologue of the human (h) polymyositis-scleroderma autoantigen (PM-Scl), which has been localized to the granular layer of the nucleolus and to distinct nucleocytoplasmic foci. The rPM-Scl and hPM-Scl homologues are 96% similar and 91% identical. We found that rPM-Scl mRNA expression was regulated by growth factor stimulation in cultured rat aortic smooth muscle cells. rPM-Scl bound to E12 and E47 but not to Id3, Gax, Myb, OCT-1, or Max. The C terminus of rPM-Scl (amino acids 283-353) interacted specifically with a 54-amino acid domain in E12 that is distinct from the bHLH domain. Finally, cotransfection of rPM-Scl and E47 specifically increased the promoter activity of a luciferase reporter construct containing an E box and did not affect the basal activity of the reporter construct. rPM-Scl appears to be a novel non-HLH-interacting partner of E12/E47 that regulates E2A protein transcription.
Kho
C J
CJ
Cardiovascular Biology Laboratory, Harvard School of Public Health, Boston, Massachusetts 02115, USA.
Huggins
G S
GS
Endege
W O
WO
Patterson
C
C
Jain
M K
MK
Lee
M E
ME
Haber
E
E
D000595:Amino Acid Sequence; D000818:Animals; D001011:Aorta / Q000378:metabolism; D001324:Autoantigens / Q000235:genetics / Q000378:metabolism*; D002478:Cells, Cultured; D018076:DNA, Complementary / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005095:Exoribonucleases; D063326:Exosome Multienzyme Ribonuclease Complex; D005786:Gene Expression Regulation; D018257:Helix-Loop-Helix Motifs / Q000235:genetics; D006801:Humans; D008969:Molecular Sequence Data; D009131:Muscle, Smooth, Vascular / Q000378:metabolism*; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics*; D051381:Rats; D051820:TCF Transcription Factors; D058125:Transcription Factor 7-Like 1 Protein; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic
D001324:Autoantigens; D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D012333:RNA, Messenger; D051820:TCF Transcription Factors; C544912:TCF7L1 protein, human; C553060:Tcf7l1 protein, rat; D058125:Transcription Factor 7-Like 1 Protein; D014157:Transcription Factors; D005095:Exoribonucleases; D063326:Exosome Multienzyme Ribonuclease Complex; C077044:EXOSC10 protein, human