2003 Fiscal Year Final Research Report Summary
Molecular analysis of androgenic effects in spermatogenesis
| Project/Area Number |
14571594
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Obstetrics and gynecology
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| Research Institution | HYOGO COLLEGE OF MEDICINE |
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Principal Investigator |
KASUMI Hiroyuki HYOGO COLLEGE OF MEDICINE, FACULTY OF MEDICINE, RESEARCH ASSOCIATE, 医学部, 助手 (00289068)
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| Co-Investigator(Kenkyū-buntansha) |
KOMORI Shinji HYOGO COLLEGE OF MEDICINE, FACULTY OF MEDICINE, PROFFSSOR, 医学部, 助教授 (60195865)
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| Project Period (FY) |
2002 – 2003
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| Keywords | androgen / androgen receptor / spermatogenesis / transition protein / CAG repeat / 精子形成 / 造精機能 |
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| Research Abstract |
Androgen(A) is an important factor for development of testis and plays a crucial role in spermatogenesis. As a large amount of androgen exists in testis and Sertoli cells have androgen receptor in testis, androgen is thought to affect spermatogenesis via Sertoli cells. However, the role of androgen is still unclear in Sertoli cells. On the other hand, it was also reported that germ cells such as spermatogonia or spermatocytes had androgen receptor in human. Therefore, it is possible for androgen to affect directly germ cells in spermatogenesis.
Generally, androgen affects the expression of target genes via androgen receptor(AR). Therefore, the defects of the androgen receptor lead to various disorders of sexual development such as testicular feminization to male infertility. To date, a lot of genetic defects of androgen receptor have been reported. Among them, some mutations lead to only male infertility. The shortage or expansion of CAG repeats of AR also leads to diseases such as Kenn
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edy disease, prostate cancer or male infertility.
In this study, we analyzed the following experiments ; 1)the disorder of androgen receptor gene in azoospermic and oligozoospermic men. 2)androgenic effects of the expression of transition protein in germ cell.
First, we analyze the mutation of androgen receptor and number of GAG repeat in 19 azoospermic and 117 oligozoospermic men. No mutations of androgen receptor were identified. 9 of 117 oligozoospermic men have 14 or 15 CAG repeats, whereas 136 normal fertile men showed more than 16 CAG repeats. The shortage of CAG repeats seems to be related to spermatogenic failure.
Second, we analyzed the androgenic effect in the expression of transition protein 1 and 2(TP1,2). TP1 and TP2 play an important role in condensing the chromosome during spermatogenesis. In the experiment with knockout mice of TP1 and TP2,a spermatogenic failure was pointed out, suggesting that the expression of TP1 and TP2 are important for spermatogenesis. The 5' region of TP1 and TP2 were isolated and cloned into a reporter plasmid with luciferase gene. Human AR genes with various CAG repeats(12,15,22 or 43 repeats) were also cloned into expression vectors. These plasmids were cotransfected into COS 7 cells by electroporation. Luciferase activities were measured with or without dihydrotestosterone(DHT). The increase of luciferase activity was identified in COS 7 cells transfected AR with 22 CAG repeats(wild type). On the other hand, any increase of luciferase activities were not identified in COS7 cells transfected AR with excessively short CAG repeats of 12 and 15 or with an excessively long CAG repeats of 43. The gel mobility shift assays of 5' region of TP1 and TP2 were performed for analyzing the binding region in COS 7 cell transfected with wild type AR. The 5' region(-754~-471bp) of TP1 and 5' region(-1218~-858bp) of TP2 were respectively identified as the binding site of nuclear proteins. The footprint assays of these binding regions were performed. The deformed(Dfd) motif, which was the binding site of homeodomain protein Dfd, was identified in TP1. The androgen responsive element like motif was identified in TP2. In summary, androgen affects the; expression of TP1 via a Dfd like molecules and the expression of TP2 via A-AR complex in germ cells.
Finally, the shortage of CAG repeats of AR is related to the disorder of spermatogenesis, whereas the point mutation of AR in infertile males with spermatogenic failure is rare. Androgen affects the expression of TP1 and TP2 in germ cells. In summary, androgen affects the spermatogenesis in germ cells. Less
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Research Products
(1 results)
