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 2.3.2.13) 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-terminal 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.
Sugino
Hiroyuki
H
Department of Applied Biochemistry, Hiroshima University, Japan.
Terakawa
Yudai
Y
Yamasaki
Akiko
A
Nakamura
Kazuhiro
K
Higuchi
Yoshiaki
Y
Matsubara
Juro
J
Kuniyoshi
Hisato
H
Ikegami
Susumu
S
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002467:Cell Nucleus / Q000201:enzymology*; D018076:DNA, Complementary; D004591:Electrophoresis, Polyacrylamide Gel; D004625:Embryo, Nonmammalian / Q000201:enzymology; D047108:Embryonic Development; D018507:Gene Expression Regulation, Developmental; D015971:Gene Expression Regulation, Enzymologic; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D013215:Starfish / Q000196:embryology*; D013347:Subcellular Fractions / Q000201:enzymology; D011503:Transglutaminases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism
D018076:DNA, Complementary; D009687:Nuclear Proteins; D011503:Transglutaminases