1992 Fiscal Year Final Research Report Summary
Studies on the transcriptional regulatory factors controlling the expression of hCG and LH gene
| Project/Area Number |
03670785
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Obstetrics and gynecology
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| Research Institution | Kobe University |
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Principal Investigator |
KATAYAMA Kazuaki Kobe University Hospital, Assistant Professor, 医学部附属病院, 講師 (70112084)
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| Co-Investigator(Kenkyū-buntansha) |
MOCHIZUKI Matsuto Kobe University School of Medicine, Professor, 医学部, 教授 (80030922)
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| Project Period (FY) |
1991 – 1992
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| Keywords | hCGbeta gene / LHbeta gene / trophoblast / footprint assay / gel shift assay |
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| Research Abstract |
The hCGb subunit is encoded by a cluster of six genes (or pseudogenes). Linked to this cluster is the single gene encoding the related LHbeta subunit. The general structure of these genes is very similar. hCGbeta genes are expressed mainly in first trimester placenta and LHbeta gene is expressed in pituitary gland. In this project, we tried to elucidate what factors control the tissue and stage specific expression of hCGbeta gene and LHbeta gene. Promoter region of these genes were isolated and used for footprint assays and gel shift assays. Although the footprint protection pattern of the hCGbeta gene fragment and LHbeta gene fragment using trophoblastic nuclear extract was very similar, there was a region LHbeta was protected but hCGbeta was not protected. Gel shift assays showed the factor which binds to the region was expressed in tissues except pituitary. It suggests that the factor suppresses expression of LHbeta gene. In vitro mutagenesis to make LHbeta promoter mutants substituted with the hCGbeta nucleotide sequence was made to analyze key sequences to acquire activity in trophoblasts.
We also performed footprint assays of hCGbeta gene using trophoblastic nuclear extracts from various stage of pregnancy. They did not show marked difference. Probably there are many nuclear factors binding to the same domain and it is hard to detect change of some factors.
To know the difference of the active hCGbeta gene and inactive hCGbeta gene, upstream sequence of hCGbeta gene 5 and hCGbeta gene 7 were used for footprint assays. We could not detect visible change of the protection pattern. It suggests that there may be factors we cannot detect by footprint assay.
The information obtained here provides a foundation for further studies on nuclear factors binding to this region regulating hCGbeta gene and LHbeta gene.
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