MSJ-1, a new member of the DNAJ family of proteins, is a male germ cell-specific gene product.
A cDNA encoding for a new member of the DnaJ protein family has been isolated by screening a mouse spermatogenic cell expression library. The full-length cDNA obtained by extension of the original clone with RT-PCR has been characterized with respect to its DNA sequence organization and expression. The predicted open reading frame encodes a protein of 242 amino acid residues whose sequence is similar to that of bacterial DnaJ proteins in the amino-terminal portion since it contains the highly conserved J domain which is present in all DnaJ-like proteins and is considered to have a critical role in DnaJ protein-protein interactions. In contrast, the middle and carboxyl-terminal regions of the protein are not similar to any other DnaJ proteins, with the exception of the human neuronal HSJ-1 with which displays a 48% identity in a 175-amino-acid overlap. Analysis of RNAs from a wide spectrum of mouse somatic tissues, including the brain, and from ovary and testis reveals that the gene is specifically expressed in testis only. Developmental Northern blot analysis of testis RNA from mice of different ages and in situ hybridization on juvenile and adult testis sections demonstrate that the mRNA is first transcribed in spermatids. A similar pattern of expression is exhibited also in rat testis. Based upon all these observations, we have named this novel mouse gene, MSJ-1, for mouse sperm cell-specific DNAJ first homolog.
Berruti
G
G
Department of Biology, University of Milan, Italy. berruti@imiucca.csi.unimi.it
Perego
L
L
Borgonovo
B
B
Martegani
E
E
D000367:Age Factors; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D018076:DNA, Complementary / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D015723:Gene Library; D005796:Genes; D050956:HSP40 Heat-Shock Proteins; D006360:Heat-Shock Proteins / Q000096:biosynthesis / Q000145:classification* / Q000235:genetics*; D006801:Humans; D017403:In Situ Hybridization; D008297:Male; D051379:Mice; D018832:Molecular Chaperones / Q000096:biosynthesis / Q000235:genetics; D008969:Molecular Sequence Data; D005810:Multigene Family; D016366:Open Reading Frames; D051381:Rats; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity; D013090:Spermatocytes / Q000737:chemistry*; D013737:Testis / Q000737:chemistry / Q000254:growth & development
D018076:DNA, Complementary; C494642:Dnajb3 protein, mouse; D050956:HSP40 Heat-Shock Proteins; D006360:Heat-Shock Proteins; D018832:Molecular Chaperones