To identify the target RNAs regulated by DAZL and characterize the effect of Single-Nucleotide Polymorphism on DAZL’s function

• Main Authors: Ting-yen Chen, 陳亭燕
• Other Authors: Pao-link Kuo
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/82815723884764812966

碩士 === 國立成功大學 === 生物化學研究所 === 97 === Infertility affects 15% of all couples. Deleted in Azoospermia (DAZ) gene was isolated from the AZFc region of the human Y chromosome that is frequently deleted in infertile men. DAZ-like (DAZL) is an autosomal homolog located on chromosome 3p24. In human beings, DAZL expresses in germ cells with different developmental stages, from spermatogonia, meiotic spermatocytes to mature spermatozoa. Although DAZL is essential for spermatogenesis, the exact function remains undefined. It has been proposed that DAZL binds with mRNA expressed in germ cells and control spermatogenesis at the level of translation. However, specific target mRNAs regulated by DAZL in vivo are not clear. Using RNA immunoprecipitation combined with high-throughput sequence analysis, a number of target transcripts, including NUDT21, NUP50, KLHL12, KDELR1, VAPA, ABHD2, SUPT5H, MLL3 and ATP6AP2, were identified. Among these transcripts the regulation of NUDT21, one of the CFIm subunit, by DAZL was studies. NUDT21 are highly expressed in mouse male germ cells and involve in alternative polyadenylation directed by noncanonical poly(A) signals during spermatogenesis. Previously, we have identified several mutations and single nucleotide polymorphisms (SNP) of DAZL, which associated with spermatogenic failure. To characterize the functional role of DAZL polymorphisms or mutations, RNA-IP and S6-IP were used to examine the binding activity and translational efficiency of NUDT21, respectively. The binding activity was increased while the translational efficiency was decreased in the existence of normal DAZL. In contrast, the polymorphism of DAZL, A to G transition at nucleotide 386, was associated with decreased binding activity and increased translational efficiency for NUDT21. These data support NUDT21 as a candidate target of DAZL-mediated translation and suggest that DAZL may indirectly participate in alternative polyadenylation during spermatogenesis.