Rat pineal S-antigen: sequence analysis reveals presence of alpha-transducin homologous sequence.
S-antigen (S-Ag) is a soluble, highly antigenic protein, the administration of which induces autoimmune uveitis. This protein is found in the retina and pineal. Retinal S-Ag from three species has been sequenced. In this study rat pineal S-Ag was sequenced. Clones were isolated from a rat pineal lambda gt11 cDNA library by probing with a 300 bp fragment of mouse retinal S-Ag cDNA containing the 5'-coding region. The largest clone isolated (RPS-118; 1364 bp) contained the entire coding sequence. Comparison of the rat pineal and mouse retinal S-Ag nucleotide sequences indicated a high homology (95%). The deduced amino acid sequence was found to contain 403 residues (congruent to 44 992 Da). Comparison of the rat pineal and mouse retinal S-Ag amino acid sequences also revealed high homology (97%). The similarity of both the nucleotide and amino acid sequences of rat pineal and mouse retinal S-Ag indicates that expression of the S-Ag gene in both tissues is similar. Further analysis of the rat pineal S-Ag sequence indicated that it contained essentially the same major uveitopathogenic region of S-Ag present in bovine retina; minor uveitopathogenic sites were somewhat different. As is true of retinal S-Ag, rat pineal S-Ag contains the same consensus phosphoryl-binding site present in many GTP/GDP-binding proteins and a homologous sequence found in the C-terminus of alpha-transducin. These sequences may play a role in the action of pineal S-Ag in transmembrane signal transduction.
Abe
T
T
Molecular Biology Section, National Eye Institute, Bethesda, MD 20892.
Yamaki
K
K
Tsuda
M
M
Singh
V K
VK
Suzuki
S
S
McKinnon
R
R
Klein
D C
DC
Donoso
L A
LA
Shinohara
T
T
D000595:Amino Acid Sequence; D000818:Animals; D000941:Antigens; D019393:Arrestin; D001324:Autoantigens; D001483:Base Sequence; D001665:Binding Sites; D005136:Eye Proteins; D005786:Gene Expression Regulation; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D010870:Pineal Gland / Q000276:immunology*; D051381:Rats; D011919:Rats, Inbred Strains; D012160:Retina / Q000276:immunology; D012689:Sequence Homology, Nucleic Acid; D015293:Transducin
D000941:Antigens; D019393:Arrestin; D001324:Autoantigens; D005136:Eye Proteins; D015293:Transducin