RT Journal Article
SR Electronic
T1 Genetic and Functional Analysis of Human P2X5 Reveals a Distinct Pattern of Exon 10 Polymorphism with Predominant Expression of the Nonfunctional Receptor Isoform
JF Molecular Pharmacology
JO Mol Pharmacol
FD American Society for Pharmacology and Experimental Therapeutics
SP 953
OP 960
DO 10.1124/mol.110.063636
VO 77
IS 6
A1 Smita Kotnis
A1 Brendan Bingham
A1 Dmitry V. Vasilyev
A1 Scott W. Miller
A1 Yuchen Bai
A1 Sarita Yeola
A1 Pranab K. Chanda
A1 Mark R. Bowlby
A1 Edward J. Kaftan
A1 Tarek A. Samad
A1 Garth T. Whiteside
YR 2010
UL http://molpharm.aspetjournals.org/content/77/6/953.abstract
AB P2X5 is a member of the P2X family of ATP-gated nonselective cation channels, which exist as trimeric assemblies. P2X5 is believed to trimerize with another member of this family, P2X1. We investigated the single-nucleotide polymorphism (SNP) at the 3′ splice site of exon 10 of the human P2X5 gene. As reported previously, presence of a T at the SNP location results in inclusion of exon 10 in the mature transcript, whereas exon 10 is excluded when a G is present at this location. Our genotyping of human DNA samples reveals predominance of the G-bearing allele, which was exclusively present in DNA samples from white American, Middle Eastern, and Chinese donors. Samples from African American donors were polymorphic, with the G allele more frequent. Reverse transcription-polymerase chain reaction analysis of lymphocytes demonstrated a 100% positive correlation between genotype and P2X5 transcript. Immunostaining of P2X1/P2X5 stably coexpressing cell lines showed full-length P2X5 to be expressed at the cell surface and the exon 10-deleted isoform to be cytoplasmic. Fluorometric imaging-based pharmacological characterization indicated a ligand-dependent increase in intracellular calcium in 1321N1 astrocytoma cells transiently expressing full-length P2X5 but not the exon 10-deleted isoform. Likewise, electrophysiological analysis showed robust ATP-evoked currents when full-length but not the exon 10-deleted isoform of P2X5 was expressed. Taken together, our findings indicate that most humans express only a nonfunctional isoform of P2X5, which is in stark contrast to what is seen in other vertebrate species in which P2X5 has been studied, from which only the full-length isoform is known.Copyright © 2010 The American Society for Pharmacology and Experimental Therapeutics