title: The eighth Cct gene, Cctq, encoding the theta subunit of the cytosolic chaperonin containing TCP-1.
abstract: The chaperonin containing t-complex polypeptide 1 (TCP-1), as one of its subunits, CCT, is a cytosolic heterooligomeric molecular chaperone assisting in the folding of proteins in eukaryotic cytosol. We have isolated a Tcp-1-related 119-bp cDNA fragment from a human cDNA library by polymerase chain reaction, and cloned full-length mouse cDNAs orthologous to the human cDNA by hybridization. The nucleotide (nt) sequence of the longest mouse clone (1844 bp) shows an open reading frame (ORF) encoding a TCP-1-related polypeptide of 548 amino acids (aa) (59,562 Da). This gene is different from Tcp-1 and the six Tcp-1-related genes reported previously, Tcp-1 (Ccta), Cctb, Cctg, Cctd, Ccte, Cctz and Ccth, which encode subunits of CCT. The product of the novel gene was analysed using an antibody raised against the C terminus of the polypeptide deduced from the nt sequence. We found that this gene encodes a subunit of CCT (polypeptide S1; 62 kDa and pI 6.25 by two-dimensional gel analysis). We have named it Cctq, encoding the theta subunit of CCT (CCT theta). The aa sequence of CCT theta shows 23-29% identity to the other CCT subunits, alpha, beta, gamma, delta, epsilon, zeta and eta, and 29% identity to the archaebacterial chaperonin TF55. CCT theta also contains the motifs common to all the other subunits of CCT which are postulated to be involved in ATPase activity.
authors.affiliation: Institute of Cancer Research, Chester Beatty Laboratories, London, UK.
authors.forename: H
authors.initials: H
authors.lastname: Kubota
authors.forename: G
authors.initials: G
authors.lastname: Hynes
authors.forename: K
authors.initials: K
authors.lastname: Willison
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001105:Archaea / Q000235:genetics; D001483:Base Sequence; D056404:Chaperonin Containing TCP-1; D018833:Chaperonins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics*; D003001:Cloning, Molecular; D017124:Conserved Sequence; D003600:Cytosol / Q000737:chemistry; D018076:DNA, Complementary / Q000235:genetics; D015180:Electrophoresis, Gel, Two-Dimensional; D006801:Humans; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D005810:Multigene Family; D009928:Organ Specificity; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics; D010802:Phylogeny; D017510:Protein Folding; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D013737:Testis / Q000737:chemistry
chemical_list: D018076:DNA, Complementary; D010446:Peptide Fragments; C533315:Tcp1 protein, mouse; D056404:Chaperonin Containing TCP-1; D018833:Chaperonins