title: Deduced primary structure of a Xenopus proteasome subunit XC3 and expression of its mRNA during early development.
abstract: Proteasome is a non-lysosomal proteinase complex ubiquitously distributed in eukaryotic cells. We isolated here the cDNA clone for one of the proteasome subunits (XC3) from Xenopus ovary cDNA libraries using rat RC3 cDNA as a prove. The cDNA is 885 bp long and encodes 234 amino acids. The deduced amino acid sequence is highly homologous (95.3%) to those of rat RC3 and human HC3 subunits. The mRNA for XC3 is one of the maternal mRNAs and detected at all the embryonic stages investigated, but its level changes in a characteristic way especially at the gastrula stage. We suggest that the highly conserved XC3 subunit plays an essential role in proteasome function and also that during Xenopus embryogenesis mRNA for XC3 subunit is replaced from maternal to newly-synthesized one probably around the gastrula stage.
authors.affiliation: Laboratory of Molecular Embryology, Faculty of Science, University of Tokyo, Japan.
authors.forename: G
authors.initials: G
authors.lastname: Fujii
authors.forename: K
authors.initials: K
authors.lastname: Tashiro
authors.forename: Y
authors.initials: Y
authors.lastname: Emori
authors.forename: K
authors.initials: K
authors.lastname: Saigo
authors.forename: K
authors.initials: K
authors.lastname: Tanaka
authors.forename: K
authors.initials: K
authors.lastname: Shiokawa
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D003001:Cloning, Molecular; D003546:Cysteine Endopeptidases / Q000235:genetics*; D004247:DNA / Q000235:genetics / Q000302:isolation & purification; D004625:Embryo, Nonmammalian / Q000502:physiology; D005260:Female; D005775:Gastrula / Q000502:physiology; D006801:Humans; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000235:genetics*; D010053:Ovary / Q000201:enzymology*; D046988:Proteasome Endopeptidase Complex; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics*; D051381:Rats; D012689:Sequence Homology, Nucleic Acid; D014981:Xenopus
chemical_list: D046911:Macromolecular Substances; D009097:Multienzyme Complexes; D012333:RNA, Messenger; D004247:DNA; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex