| Project/Area Number |
04454021
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
動物発生・生理学
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| Research Institution | HOKKAIDO UNIVERSITY |
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Principal Investigator |
KATAGIRI Chiaki FACULTY OF SCIENCE,HOKKAIDO UNIV., PROFESSOR, 理学部, 教授 (90000827)
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| Co-Investigator(Kenkyū-buntansha) |
TAKAMUNE Kazufumi FACULTY OF SCIENCE,KUMAMOTO UNIV., INSTRUCTOR, 理学部, 講師 (20206882)
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| Project Period (FY) |
1992 – 1994
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| Project Status |
Completed (Fiscal Year 1994)
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| Budget Amount *help |
¥7,000,000 (Direct Cost: ¥7,000,000)
Fiscal Year 1994: ¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 1993: ¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 1992: ¥3,700,000 (Direct Cost: ¥3,700,000)
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| Keywords | SPERM NUCLEAR BASIC PROTEINS / Xenopus laevis / SPERMATOGENESIS / cDNA / AMINO ACID SEQUENCE / GENE STRUCTURE / GENOMIC ANALYSIS / TRANSCRIPTIONAL REGULATION / 両生類 / 塩基配列 / ゲノミックDNA / 卵膜ライシン / cDNAライブラリー |
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| Research Abstract |
Nuclear basic proteins of an anuran amphibian Xenopus laevis consist of 6 sperm specific proteins (SPs 1-6) in addition to somatic core histones. Analyzes based on cDNAs indicated that SP4 and SP5 each comprising 78- and 74 amino acids have properties intermediate between typical protamines and somatic histones, and are present in a ratio of 5/1 (SP4/SP5). Construction of restriction maps based on Southern blot analyzes of genomic DNA revealed the presence of a total of five SP4 genes which are arranged in a tandemly repeated array forming a cluster of simple multigenes per haploid genome, over a range of 20kbp. Each gene contains an intron, typical TATA and CCAAT boxes in the 5'-flanking region, and a polyadenylation signal in the 3'-flanking region. In addition, there are three regions of extensive sequence homology within the upstream non-coding region among three SP4 genes which were totally seuquenced for over 10kbp, suggesting its possible relevance to the expression of these genes at a particular phase of spermatogenesis and/or in testis. Among the five tandemly arranged genes, the one located at the most upstream position differed from others in possessing a single base substitution which could give rise to an amino acid replacement of Ala to Ser. The presence of this particular variant of SP4 was confirmed by reversed-phase HPLC fractionation of sperm nuclear proteins, and its relative amout to SP4 was 1/4, reflecting the relative amount of relevant genes. Similar measurements of the amounts of protein and mRNA,and the number of genes for SP5 relative to SP4 indicated that in all these parameters the ratio was consistently 1/5 (SP5/SP4). Thus the deposition of different amounts of 'SP5 and SP4 (including its variant) in sperm nuclei reflects the relative number of these genes in the genome.
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