Mouse synexin (annexin VII) polymorphisms and a phylogenetic comparison with other synexins.
Two sets of cDNAs encoding mouse synexin were isolated from a liver cDNA library and sequenced. The coding regions of synexin clones show 99% identity. By contrast, the two mouse synexin cDNAs differ in a number of ways in both 5' and 3' non-coding regions. The two sets of cDNA encode a polypeptide of 463 amino acid residues which has a deduced molecular mass of 50 kDa. The amino acid sequence of mouse synexin shows a high degree of similarity to both the unique N-terminal domain and the highly conserved C-terminal domain of previously cloned human synexin. Northern-blot analysis using mouse liver polyadenylated RNA revealed two transcripts of 1.8 kb and 2.6 kb, corresponding to group I and group II respectively. Further hybridization analysis using specific sequences from each set of clones showed that the two sizes of mRNAs differ in the length of the 3' non-coding region which corresponded to the cDNAs. Both mouse liver synexin and recombinant mouse synexin expressed in Escherichia coli reacted after Western-blot analysis with a goat antibody against bovine synexin. Only in the larger group-II cDNAs do we find point mutations leading to amino acid replacements of Ser to Ala at residue 145 in the unique N-terminal domain, and of Ala to Gly at residue 304 in the transition zone between repeats II and III. We conclude from a comparison of mouse, human and Dictyostelium synexins that changes occur predominantly in the hydrophobic N-terminal domain, or, in the C-terminal region at the ends of some predicted alpha-helices, on the hydrophobic face of the amphipathic C-helices, and within a lengthy non-helical domain connecting major repeats II and III.
Zhang-Keck
Z Y
ZY
Laboratory of Cell Biology and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892.
Burns
A L
AL
Pollard
H B
HB
D000595:Amino Acid Sequence; D000818:Animals; D017310:Annexin A7 / Q000235:genetics*; D001483:Base Sequence; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics; D051379:Mice / Q000235:genetics*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010802:Phylogeny; D011061:Poly A / Q000235:genetics; D011110:Polymorphism, Genetic; D011487:Protein Conformation; D012333:RNA, Messenger / Q000235:genetics; D017386:Sequence Homology, Amino Acid
D017310:Annexin A7; D012333:RNA, Messenger; D011061:Poly A