Human MN/CA9 gene, a novel member of the carbonic anhydrase family: structure and exon to protein domain relationships.
We have isolated, sequenced, and characterized a human MN/CA9 gene. This gene is a novel member of the carbonic anhydrase (CA) family, which codes for widely distributed catalysts of the reversible conversion of carbon dioxide to carbonic acid. So far, MN/CA IX is the only tumor-associated CA isoenzyme. The entire genomic sequence of MN/CA9, including the 5'-flanking region, encompasses 10.9 kb. The coding sequence is divided into 11 exons, whose organization and relationships to predicted protein domains suggest that the gene arose by exon shuffling. Exon 1 encodes a signal peptide and a proteoglycan-related region. Exons 2-8 code for a CA domain with a highly conserved active site. The exon/intron pattern of the CA coding region is similar but not identical to other described animal kingdom alpha-CA genes. Exons 10 and 11 encode a transmembrane anchor and an intracytoplasmic tail, respectively. We have also determined the transcription initiation and termination sites by RNase protection assay and analyzed the 3. 5-kb region upstream of the MN/CA9 gene. Sequence of the proximate 5' end of the flanking region shows extensive homology to the long terminal repeats of HERV-K endogenous retroviruses. The putative MN/CA9 promoter immediately preceding the transcription start site does not possess a TATA box, but contains consensus sequences for the AP1, AP2, p53, and Inr transcription factors. This study will allow further investigations of the molecular events regulating expression of MN/CA IX as well as elucidation of its biological function.
Opavský
R
R
Institute of Virology, Slovak Academy of Sciences, Bratislava, Slovak Republic.
Pastoreková
S
S
Zelník
V
V
Gibadulinová
A
A
Stanbridge
E J
EJ
Závada
J
J
Kettmann
R
R
Pastorek
J
J
D000595:Amino Acid Sequence; D001483:Base Sequence; D001665:Binding Sites; D015139:Blotting, Southern; D002256:Carbonic Anhydrases / Q000096:biosynthesis* / Q000235:genetics*; D003001:Cloning, Molecular; D017124:Conserved Sequence; D005091:Exons; D015698:Genomic Library; D006367:HeLa Cells; D006801:Humans; D007438:Introns; D007527:Isoenzymes / Q000096:biosynthesis* / Q000235:genetics*; D008969:Molecular Sequence Data; D005810:Multigene Family; D011401:Promoter Regions, Genetic; D012091:Repetitive Sequences, Nucleic Acid; D017386:Sequence Homology, Amino Acid; D014158:Transcription, Genetic
D007527:Isoenzymes; D002256:Carbonic Anhydrases