Biochemical and functional characterizations of a DEAD box containing protein, DDX1

• Main Authors: Hui-Chen Chen, 陳慧蓁
• Other Authors: Sheng —Chung Lee
• Format: Others
• Language: en_US
• Published: 2001
• Online Access: http://ndltd.ncl.edu.tw/handle/61617922361630179344

碩士 === 國立臺灣大學 === 分子醫學研究所 === 89 === hnRNP K is a multifunctional protein known to be involved in regulation of transcription, translation, nuclear transport and signal transduction. Some hnRNP K- associated proteins have been isolated. In the thesis, I defined a new member of hnRNP K interacting protein, DDX1. DDX1 is a member of the DEAD box protein family, members of the DEAD-box family contain eight conserved motifs with demonstrated ATPase activity. In addition to the reported DDX1, a longer form (DDX1(#4)) with an extra 121 nucleotides fragment located between nucleotides 241 and 242 of DDX1(#3) was isolated. Both forms of DDX1s can interact with hnRNP K in in vitro and in vivo assays. The region spanning from amino acid 1-276 of hnRNP K is apparently responsible for its physical interaction with DDX1. The ATPase activity of the purified recombinant DDX1(#3) protein was stimulated by some single-stranded RNAs, including poly(A), poly(U) and poly(C), and yeast and HeLa cell total RNA, but not by DNAs. In the presence of hnRNP K, the ATPase activity of DDX1(#3) with poly(C) was partially (~25%) inhibited.