Cloning of cDNAs encoding human interphotoreceptor retinoid-binding protein (IRBP) and comparison with bovine IRBP sequences.
We have determined the sequence of the human interphotoreceptor retinoid-binding protein mRNA from three separately isolated cDNAs. The sequence is 4.28 kb long and encodes a protein of 1247 amino acids (aa) including a putative signal peptide and propeptide. The sequence is shorter (by about 1.67 kb) than the bovine mRNA with the major difference in the lengths located in the 3'-untranslated region. We suggest that this resulted from an insertion in the bovine gene or a large deletion from the human gene. The insertion/deletion is flanked on either side by sequences that are similar in the bovine and human sequences. Like the bovine polypeptide, the deduced protein sequence from the human cDNA contains a fourfold repeat, with each repeat containing about 300 aa. Among the four repeats, the identity is about 30-40%. The identity between the complete bovine and human polypeptide sequences is 84%. The identity between the nucleotide sequences is 83% (excluding the major insertion/deletion). Comparison with the bovine gene indicates that the human sequence may lack about 5-10 bp at the 5' end of the cDNA; it, however, includes a poly(A) tail at the 3' end. Thus, the human sequence is virtually full length, is similar to the bovine sequence, and contains a striking fourfold repeat.
Si
J S
JS
Laboratory of Retinal Cell and Molecular Biology, National Eye Institute, Bethesda, MD 20892.
Borst
D E
DE
Redmond
T M
TM
Nickerson
J M
JM
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002417:Cattle; D003001:Cloning, Molecular; D003062:Codon; D004247:DNA / Q000235:genetics; D005136:Eye Proteins / Q000235:genetics* / Q000378:metabolism; D006031:Glycosylation; D006801:Humans; D007438:Introns; D008969:Molecular Sequence Data; D021382:Protein Sorting Signals / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D012091:Repetitive Sequences, Nucleic Acid; D012177:Retinol-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D012689:Sequence Homology, Nucleic Acid; D000099214:Retinol-Binding Proteins, Interstitial
D003062:Codon; D004247:DNA; D005136:Eye Proteins; D021382:Protein Sorting Signals; D012333:RNA, Messenger; D012177:Retinol-Binding Proteins; D000099214:Retinol-Binding Proteins, Interstitial