Regulation of porcine pituitary glycoprotein hormone alpha subunit gene with LIM-homeobox transcription factor Lhx3.
The aim of this study was to characterize the promoter activity of the porcine pituitary glycoprotein hormone common alpha gene (Cga) promoter (-1059/+12) and the role of LIM homeodomain transcription factor Lhx3. A transfection assay using Chinese hamster ovary (CHO) cells showed that the -1059/-101 region of the Cga promoter definitely responds to Lhx3 and that the -1059/-240 region exhibits a high basal transcriptional level in a pituitary-derived cell line, LbetaT2. A DNA binding and DNase I footprinting assay demonstrated that Lhx3 has seven binding sites in the -1059/+12 region of Cga, including a pituitary glycoprotein hormone basal element (PGBE) known as a LIM homeodomain factor-binding site. A transfection assay of the sequence of Lhx3-binding sites fused with minimal promoter vector confirmed their Lhx3-dependent stimulations in LbetaT2 cells. RT-PCR analysis of porcine pituitary ontogeny demonstrated that porcine Lhx3 showed striking changes of expression in both sexes during the fetal period but a stable high level of expression after birth. Thus, the porcine Cga promoter is regulated by Lhx3 through seven sites in the distal and proximal regions.
Susa
Takao
T
Division of Life Science, Graduate School of Agriculture, Meiji University, Kawasaki, Japan.
Ishikawa
Akio
A
Kato
Takako
T
Nakayama
Michie
M
Kitahara
Kousuke
K
Kato
Yukio
Y
D000818:Animals; D001665:Binding Sites; D016466:CHO Cells; D002460:Cell Line; D045744:Cell Line, Tumor; D006224:Cricetinae; D003412:Cricetulus; D004247:DNA / Q000378:metabolism; D003850:Deoxyribonuclease I / Q000378:metabolism; D005786:Gene Expression Regulation; D015292:Glycoprotein Hormones, alpha Subunit / Q000096:biosynthesis* / Q000235:genetics*; D018398:Homeodomain Proteins / Q000096:biosynthesis*; D060850:LIM-Homeodomain Proteins; D051379:Mice; D017434:Protein Structure, Tertiary; D013552:Swine; D014157:Transcription Factors
D015292:Glycoprotein Hormones, alpha Subunit; D018398:Homeodomain Proteins; D060850:LIM-Homeodomain Proteins; C094898:Lhx3 protein; D014157:Transcription Factors; D004247:DNA; D003850:Deoxyribonuclease I