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研究発表を行った学会；
・第４０回日本発生生物学会・第５９回日本細胞生物学会　合同大会、2007年 5月28~30日(福岡)

タイトル；出芽酵母における新規細胞内局在化RNAの同定：βNAC mRNAは細胞質にかたまりを形成して局在する.
Identification of novel localized RNAs in yeast : mRNA for β-subunit of NAC accumulates to form a large granule in the cytoplasmin S.cerevisiae.

発表者；　林　紗千子　氏
　　　（熊本大学大学院自然科学研究科理学専攻生命科学コース　谷研究室）
Abstract；
RNA localization is a common mechanism for targeting proteins to specific regions of a cell, which causes cell’s polarization and sometimes an asymmetric division. To find new localized RNAs, we started genome-wide screening of localized RNAs in S.cerevisiae. In this study, U1A tag-fused RNAs were co-expressed with U1A protein conjugated to GFP in the cell. The localization of RNAs was detected by fluorescence microscopy. So far, we observed 8400 RNA molecules and found many RNA molecules in specific regions in the cell. Of those, EGD1 mRNA molecules were found to accumulate as a large granule in the cytoplasm. EGD1 encodes a β-subunit of the nascent polypeptide-associated complex (NAC) in S .cerevisiae. NAC is conserved throughout the eukaryotes. It has been suggested that NAC contributes to the protein folding of nascent polypeptide chains. To check the effect of U1A- tag on the accumulated localization of EGD1 mRNA, we did in situ hybridization analysis with specific probes of EGD1 mRNA. EGD1 mRNAs expressed under the control of its endogenous promoter in a multi-copy plasmid were also detected in a large granule in the cytoplasm. We observed various kinds of EGD1 mRNA constructs to identify a region required for the localization. The specific localization of EGD1 mRNAs required both EGD1 ORF and 5’UTR of EGD1 mRNA. In addition, EGD1 mRNAs were co-localized with Dcp1p, Xrn1p and Dhh1p. These proteins are known to be components of P-body, cytoplasmic foci for degradation and translational regulation of mRNAs. We are now investigating whether the accumulated localization of EGD1 mRNAs is related to translational regulation of Egd1p.