Molecular cloning and characterization of TIEG2 reveals a new subfamily of transforming growth factor-beta-inducible Sp1-like zinc finger-encoding genes involved in the regulation of cell growth.
Sp1-like zinc finger transcription factors are involved in the regulation of cell growth and differentiation. Recent evidence demonstrating that mammalian cells express novel, yet uncharacterized, Sp1-like proteins has stimulated a search for new members of this family. We and others have recently reported that the transforming growth factor (TGF)-beta-regulated gene TIEG encodes a new Sp1-like protein that inhibits cell growth in cultured cells. Here we report the identification, nuclear localization, DNA binding activity, transcriptional repression activity, and growth inhibitory effects of TIEG2, a novel TGF-beta-inducible gene related to TIEG. TIEG2 is ubiquitously expressed in human tissues, with an enrichment in pancreas and muscle. TIEG2 shares 91% homology with TIEG1 within the zinc finger region and 44% homology within the N terminus. Biochemical characterization reveals that TIEG2 is a nuclear protein, which, as predicted from the primary structure, specifically binds to an Sp1-like DNA sequence in vitro and can repress a promoter containing Sp1-like binding sites in transfected Chinese hamster ovary epithelial cells. Furthermore, functional studies using [3H]thymidine uptake and MTS (3-(4, 3-dimethyltiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-su lfophenyl)-2 H-tetrazolium) assays demonstrate that the overexpression of TIEG2 in Chinese hamster ovary cells inhibits cell proliferation. Thus, TIEG2, together with TIEG1, defines a new subfamily of TGF-beta-inducible Sp1-like proteins involved in the regulation of cell growth.
Cook
T
T
Gastroenterology Research Unit, Saint Marys Hospital, Mayo Clinic, Rochester, Minnesota 55905, USA.
Gebelein
B
B
Mesa
K
K
Mladek
A
A
Urrutia
R
R
D000595:Amino Acid Sequence; D000818:Animals; D017209:Apoptosis / Q000235:genetics; D051017:Apoptosis Regulatory Proteins; D016466:CHO Cells / Q000166:cytology; D018797:Cell Cycle Proteins / Q000737:chemistry*; D002455:Cell Division / Q000502:physiology*; D003001:Cloning, Molecular; D006224:Cricetinae; D004268:DNA-Binding Proteins / Q000737:chemistry*; D051765:Early Growth Response Transcription Factors; D005786:Gene Expression Regulation / Q000235:genetics; D006801:Humans; D051741:Kruppel-Like Transcription Factors; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000737:chemistry; D012333:RNA, Messenger / Q000378:metabolism; D012097:Repressor Proteins / Q000737:chemistry*; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D016329:Sp1 Transcription Factor / Q000737:chemistry; D014157:Transcription Factors / Q000737:chemistry*; D016212:Transforming Growth Factor beta / Q000502:physiology*; D016335:Zinc Fingers / Q000502:physiology*
D051017:Apoptosis Regulatory Proteins; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D051765:Early Growth Response Transcription Factors; C098111:KLF10 protein, human; C115117:KLF11 protein, human; D051741:Kruppel-Like Transcription Factors; D009687:Nuclear Proteins; D012333:RNA, Messenger; D012097:Repressor Proteins; D016329:Sp1 Transcription Factor; D014157:Transcription Factors; D016212:Transforming Growth Factor beta