| Project/Area Number |
10460122
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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 |
Applied animal science
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| Research Institution | THE UNIVERSITY OF TOKYO |
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Principal Investigator |
SAKAI Senkiti THE UNIVERSITY OF TOKYO, GRADUATE SCHOOL OF AGRICULTURAL AND LIFE SCIENCES, PROFESSOR, 大学院・農学生命科学研究所, 教授 (80114487)
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| Co-Investigator(Kenkyū-buntansha) |
AOKI Fugaku THE UNIVERSITY OF TOKYO, GRADUATE SCHOOL OF FRONTIER SCIENCES, ASSOCIATE PROFESSOR, 大学院・農学生命科学研究所, 助教授 (20175160)
IMAKAWA Kazuhiko THE UNIVERSITY OF TOKYO, GRADUATE SCHOOL OF AGRICULTURAL AND LIFE SCIENCES, ASSOCIATE PROFESSOR, 大学院・農学生命科学研究所, 助教授 (00291956)
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| Project Period (FY) |
1998 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥13,100,000 (Direct Cost: ¥13,100,000)
Fiscal Year 1999: ¥3,000,000 (Direct Cost: ¥3,000,000)
Fiscal Year 1998: ¥10,100,000 (Direct Cost: ¥10,100,000)
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| Keywords | Mammary gland / Poly(A) tail / mRNA stablity / Casein mRNA / Mitochondrial DNA / Tim23 mRNA / half-life of mRNA / Lactogenesis / マウス乳腺 / メッセンジャーRNA / 離乳再哺乳 / ポリ(A)テール / RNA半減期 / カゼイン |
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| Research Abstract |
We examined the effect of the poly(A) tail length of β- and γ- casein mRNAs on the mRNA stability in the lactating mouse mammary gland. In the experiment I, the lactating mammary gland modulated acutely and reversibly the poly(A) tail length of casein mRNA depending on the accumulation and removal of gland's milk. The long poly(A) protected from mRNA degradation by RNases. Thus, casein mRNA with the short poly(A) tail had a shorter half-life than that with the long one. The poly(A) tail length of casein mRNA was examined a different stages of pregnancy and lactation. The poly(A) tail was about 30 nucleotides in length during pregnancy. Once casein mRNA was expressed, the poly(A) tail elongated to over 100 nucleotides. At the end of lactation, the mammary gland became less active in the elongation of the poly(A) tail than that at early and midlactation, and the poly(A) tail in length was shortened significantly. Casein mRNA with the long poly(A) tail was more stable than that with the shot one during lactation. We cleared that the mammary gland modulated the casein mRNA stability by changing the poly(A) tail length of casein mRNA, and that the level of casein mRNA was regulated at the posttranscriptional level. In the experiment II, we examined the expression of Tim23 mRNA at lactogenesis. Tim23, a mitochondrial of translocase of inner membrane protein, is encoded by genomic DNA. The expression of Tim23 mRNA was regulated by hormones and increased at the end of pregnancy. Hormones required for the Tim23 gene expression were essentially the same as for milk synthesis.
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