Cofactor CLIM2 promotes the repressive action of LIM homeodomain transcription factor Lhx2 in the expression of porcine pituitary glycoprotein hormone alpha subunit gene.
We have cloned a porcine orthologue of cofactor CLIM2 (Ldb1/NLI) from the porcine pituitary cDNA library by protein-protein interaction with the Yeast Two-Hybrid System using porcine Lhx2 as a bait protein. Porcine CLIM2 shows a high identity (99%) in the dimerization domain, nuclear localization signal and LIM binding domain with those of man and mouse. The expression of CLIM2 gene in the anterior pituitary lobe was detected during the porcine fetal and postnatal period by RT-PCR analysis, suggesting that this protein is constitutively expressing and plays a basic role in the anterior pituitary. Transfection assay to the pituitary tumor derived LbetaT2 cells, and the Chinese hamster ovary cells demonstrated that CLIM2 acts as a corepressor of the porcine Lhx2 function. Interestingly, CLIM2 alone apparently repressed the high level of alphaGSU gene expression in LbetaT2 cells. These data suggest that CLIM2 is a basic factor in the pituitary development and function, and plays the role of repressor to modify the function of Lhx2 on the alphaGSU gene expression.
Susa
Takao
T
Laboratory of Molecular Biology and Gene Regulation, Department of Life Science, School of Agriculture, Meiji University, Kawasaki 214-8571, Japan.
Sato
Takanobu
T
Ono
Tetsuo
T
Kato
Takako
T
Kato
Yukio
Y
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D016466:CHO Cells; D006224:Cricetinae; D018076:DNA, Complementary / Q000235:genetics; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D005260:Female; D018507:Gene Expression Regulation, Developmental; D015292:Glycoprotein Hormones, alpha Subunit / Q000235:genetics*; D018398:Homeodomain Proteins / Q000378:metabolism*; D006801:Humans; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D010903:Pituitary Gland, Anterior / Q000196:embryology / Q000254:growth & development / Q000378:metabolism; D011247:Pregnancy; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013552:Swine; D014157:Transcription Factors / Q000378:metabolism*; D014162:Transfection
D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D015292:Glycoprotein Hormones, alpha Subunit; D018398:Homeodomain Proteins; D011994:Recombinant Proteins; D014157:Transcription Factors