Characterization of two isoforms of a human DnaJ homologue, HSJ2.
Two cDNA forms were characterized for a human dnaJ homologue, HSJ2. Nucleotide sequencing showed that the gene product HSJ2 was longer than previously reported, extending its homology to other human DnaJ paralogues, and that the two cDNAs encoded two proteins as a result of alternative splicing. The products were 326 amino acids (designated as HSJ2a) and 241 amino acids (HSJ2b) in length, sharing the N-terminal 231 amino acids including the DnaJ homology region. When fused to green fluorescent protein and expressed in HeLa cells, HSJ2a was found to be localized to the nucleus, indicating that HSJ2a is a nuclear co-chaperone. HSJ2b, however, was observed throughout the cell, consistent with the elimination of a putative nuclear localization signal sequence as a result of the alternative splicing.
Hanai
Ryo
R
Department of Life Science and Frontier Project Life's Adaptation Strategies to Environmental Changes, Rikkyo (St. Paul's) University, Japan. hanai@rikkyo.ne.jp
Mashima
Keisuke
K
D017398:Alternative Splicing / Q000235:genetics*; D000595:Amino Acid Sequence; D001483:Base Sequence; D002352:Carrier Proteins; D002467:Cell Nucleus / Q000378:metabolism; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D050956:HSP40 Heat-Shock Proteins; D006367:HeLa Cells; D006360:Heat-Shock Proteins; D006801:Humans; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D020033:Protein Isoforms / Q000235:genetics; D021381:Protein Transport; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
D002352:Carrier Proteins; D018076:DNA, Complementary; C107481:DNAJA1 protein, human; D050956:HSP40 Heat-Shock Proteins; D006360:Heat-Shock Proteins; D009687:Nuclear Proteins; D020033:Protein Isoforms; D011993:Recombinant Fusion Proteins