tailieunhanh - Báo cáo khoa học: Molecular characterization of a novel nuclear transglutaminase that is expressed during starfish embryogenesis

We report the constitution and molecular characterization of a novel transglutaminase (EC ) that starts to accumulate speci®cally in thenucleus in the star®sh (Asterina pectinifera) embryo after progression through the early blastula stage. The cDNA for the nuclear transglutaminase was clonedand the cDNA-deduced sequence de®nes a single open reading frame encoding aproteinwith737 aminoacids andapredictedmolecularmass of 83 kDa. | Eur. J. Biochem. 269 1957-1967 2002 FEBS 2002 doi Molecular characterization of a novel nuclear transglutaminase that is expressed during starfish embryogenesis Hiroyuki Sugino Yudai Terakawa Akiko Yamasaki Kazuhiro Nakamura Yoshiaki Higuchi Juro Matsubara Hisato Kuniyoshi and Susumu Ikegami Department of Applied Biochemistry Hiroshima University Japan We report the constitution and molecular characterization of a novel transglutaminase EC that starts to accumulate specifically in the nucleus in the starfish Asterina pectinifera embryo after progression through the early blastula stage. The cDNA for the nuclear transglutaminase was cloned and the cDNA-deduced sequence defines a single open reading frame encoding a protein with 737 amino acids and a predicted molecular mass of 83 kDa. A comparison of this transglutaminase with other members of the gene family revealed an overall sequence identity of 33-41 . A special sequence feature of this transglutaminase which is not found in other transglutaminases is the presence of nuclear localization signal-like sequences in the N-terminal region. Microinjection of hybrid constructs that encode the N-ter-minal segment fused to reporter proteins into the germinal vesicle of an oocyte produced chimeric proteins by transcription-coupled translation. It was found that the N-terminal segment alone was sufficient to effect nuclear accumulation of an otherwise cytoplasmic protein. These results suggest that the nuclear accumulation of the transglutaminase may play an important role in nuclear remodeling during early starfish embryogenesis. Keywords transglutaminase nucleus starfish embryo cloning. The class of enzymes that are commonly referred to as transglutaminases TG EC are known mostly for their role in the post-translational remodeling of proteins reviewed in 1 . These enzymes catalyze protein crosslinking reactions via the formation of e- y-glutamyl lysine bonds between the