Structural characterization of the rat carboxypeptidase-E gene.
Several genomic clones encoding carboxypeptidase-E (CPE) have been isolated and partially sequenced. Southern blot analysis indicates that a single copy of this gene is present in the rat genome. The entire gene spans approximately 50 kilobases and consists of nine exons, each of which contains protein-coding regions. Only one of the exon/intron junctions of the rat CPE gene is present in a comparable position within the genes for carboxypeptidase-A and -B, both of which are only 17-21% homologous to CPE at the amino acid level. Nuclease protection analysis shows that alternative splicing of exons 7, 8, and 9 does not occur, indicating that the heterogeneity of the C-terminal region of CPE is due to posttranslational processing. Primer extension and nuclease protection analyses have identified the 5' end of CPE mRNA to be 105 nucleotides up-stream from the ATG used for protein translation. The 5' flanking region does not contain TATA and/or CCAAT boxes in the near vicinity of the transcription initiation site. The 5' flanking region is GC rich, containing 70% GC residues over nucleotides -1 to -150 (relative to the transcription initiation site). Putative consensus sites for the enhancer elements SP-1, NF-1, Pan-1, and AP-2 are present in the region from -60 to -330. Since this report describes the first neuropeptide-processing enzyme gene to be partially sequenced, it is not possible to compare the sequence with those of other processing enzymes that show similar tissue-specific expression. However, comparison of the CPE sequence with 5' flanking regions of other neuroendocrine genes has revealed a short region (12-18 nucleotides) that is highly conserved among CPE, neuropeptide-Y, oxytocin, insulin, and tyrosine hydroxylase genes.
Jung
Y K
YK
Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York 10461.
Kunczt
C J
CJ
Pearson
R K
RK
Dixon
J E
JE
Fricker
L D
LD
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D043423:Carboxypeptidase H; D002268:Carboxypeptidases / Q000235:genetics*; D003001:Cloning, Molecular; D004247:DNA / Q000737:chemistry; D005091:Exons; D015723:Gene Library; D007438:Introns; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D009928:Organ Specificity / Q000235:genetics; D014176:Protein Biosynthesis; D012326:RNA Splicing; D051381:Rats; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid
D004247:DNA; D002268:Carboxypeptidases; D043423:Carboxypeptidase H