1998 Fiscal Year Final Research Report Summary
Molecular and Cellular Biological Studies on Mechanisms for Biosynthesis and Release of Human Coagulation Factor XIII.
| Project/Area Number |
08457271
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Hematology
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| Research Institution | Yamagata University School of Medicine |
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Principal Investigator |
ICHINOSE Akitada Yamagata University, School of Medicine, Professor, 医学部, 教授 (10241689)
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| Co-Investigator(Kenkyū-buntansha) |
SOURI Masayoshi Yamagata University, School of Medicine, Instructor, 医学部, 助手 (20292419)
YAMAZAKI Tomio Yamagata University, School of Medicine, Instructor, 医学部, 助手 (00282202)
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| Project Period (FY) |
1996 – 1998
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| Keywords | Factor XIII / Transglutaminase / Cross-linking / Bleeding / Wound healing / Miscarriage / Single peptide-less / Protein transport |
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| Research Abstract |
We have identified 6 mutations in the A subunit of the gene for Factor XIII deficiency and have determined how these mutations impair A subunit synthesis. The level of mRNA was found to be greatly reduced in two cases with splicing abnormalities. Molecular modeling calculated that the Arg260Cys, Tyr283Cys, and Gly562Arg mutations as well as premature termination at codon 464, changed the conformation of the A subunit, suggesting misfolding and/or destabilization of the molecule. Recombinant A subunits bearing these mutations were expressed in mammalian or yeast cells. Results indicated that the mutants were synthesized normally, but disappeared rapidly because of their instability, We also characterized all five of the cases with B subunit deficiency that have ever been reported, and found that at least three unrelated cases share the same mutation due to a founder's effect. We therefore proposed a new classification for Factor XIII deficiency.
Promoter elements for a myeloid-enriched transcription factor (MZF- 1) and two ubiquitous transcription factors (NF- 1 and SP- 1) in the 5'-flanking region were important for basal expression of the A subunit. DNA sequences for binding of the myeloid-enriched factors (GATA-1 and Ets-1) were recognized in the upstream region, and the GATA-1 element was found to be responsible for the enhancer activity. These transcription factors play a major role in the cell-type-specific expression, which differs from other transglutaminases.
Finally, we found that monocytoid and megakaryocytoid cell lines endogeneously expressed the A subunit of Factor XIII, and the amount of expressed A subunit significantly changed during proliferation and differentiation.
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