Functional characterization of pinin dominant negative mutant with animal models

• Main Authors: Hsu Pin Wu, 吳許斌
• Other Authors: P. Ouyang
• Format: Others
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/18172199608727760335

碩士 === 長庚大學 === 生物醫學研究所 === 101 === Pinin (pnn) is a nuclear speckle-associated SR-like protein. Loss of pnn expression results in mouse early embryonic lethality and cellular apoptosis and hypomorphic reduction of pnn resulted in a wide range of developmental defects in mice. Pnn protein sequence via comparative analysis was found highly conserved from mammals to insects in the N-terminal region, but the C-terminal RS domain-containing region is absent in lower species. The N-terminal coiled-coil domain (CCD) is therefore considered important in terms of not only in functional implication but in evolution origin. To explore the biological role of pnn CCD in a physiological context and to address whether pnn mutant without the C-terminal region could replace endogenous pnn in vivo, we generated transgenic mice overexpressing mouse pnn mutant under control of human skeletal actin promoter. Here we found that overexpression of the CCD could reduce the endogenous pnn expression in cultured cell lines as well as in transgenic skeletal muscle fibers. Pnn mutant mice present reduced body mass and impaired muscle function during development. Mutant skeletal muscles show dystrophic histological features with muscle fiber heavily loaded with centrally located myonuclei. Expression profiling and pathway analysis identify over-representation genes in gene category associated with muscle contraction, specifically those related to slow type muscle fiber. Finally the relationship of muscular dystrophic phenotype caused by pnn mutant mice to human disease is discussed.