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Cloning and identification of a novel human NBCn1 splice variant
Author(s) -
Liu Ying,
Parker Mark D,
Boron Walter F
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.2_supplement.92
Subject(s) - splice , biology , complementary dna , alternative splicing , exon , genetics , cdna library , cloning (programming) , gene , gene isoform , rapid amplification of cdna ends , transmembrane protein , transmembrane domain , computational biology , molecular cloning , receptor , computer science , programming language
The electroneutral Na‐coupled HCO 3 transporter NBCn1 belongs to the SLC4 family, which includes products of 10 genes in mammals. With two alternative N‐termini (transcribed from alternative promoters, which are separated by more than 25kb in the SLC4A7 gene) and three major splice cassettes (I, II, III), SLC4A7 gene could, in principle, produce as many as 16 splice variants. Six NBCn1 variants (i.e., NBCn1A‐F) have been identified in mammals. NBCn1‐A and ‐F begin with peptide sequence MERF, whereas NBCn1‐B, ‐C, ‐D, and ‐E begin with peptide sequence MEAD. The first MERF variant was identified in the human, whereas the first MEAD variants were identified in rat. Using 5′ rapid amplification of cDNA ends, we verified the presence of the 5′‐UTR for human MEAD‐NBCn1 in human cDNA libraries from brain, heart, kidney, and liver. Using two pairs of gene‐specific primers, we cloned by nested‐PCR a new full‐length cDNA for MEAD‐NBCn1 (which we will call NBCn1‐G) from a human whole‐brain cDNA library. The novel splice variant begins with MEAD instead of MERF, and contains cassette I and III, but lacks cassette II (i.e., exon 7). In addition, we found a truncated clone of MEAD‐NBCn1 that terminates before the transmembrane domain because of the splicing out of exon 13. In conclusion, we cloned and sequenced a novel full‐length NBCn1 variant as well as a cDNA corresponding to an N‐terminal fragment.