The human P2X4 receptor gene is alternatively spliced.
ATP acts as a fast excitatory neurotransmitter by binding to a large family of membrane proteins, P2X receptors, that have been shown to be ligand-gated, non-selective cation channels. We report the cloning of a full-length and alternatively spliced form of the human P2X4 gene. Clones were identified from a human stomach cDNA library using a rat P2X4 probe. Nucleotide sequence analysis of positive clones identified the full-length human P2X4 cDNA, which codes for a 388-residue protein that is highly homologous (82%) to the rat gene, and an alternatively spliced cDNA. In the alternatively spliced cDNA, the 5'-untranslated region and the first 90 amino acids in the coding region of full-length human P2X4 are replaced by a 35 amino acid coding sequence that is highly homologous with a region of chaperonin proteins in the hsp-90 family. The open reading frames of the full-length and splice variant clones were confirmed by in vitro translation. Northern analysis indicated expression of the full-length P2X4 message in numerous human tissues including smooth muscle, heart, and skeletal muscles. Alternatively spliced RNAs were identified in smooth muscle and brain by RT-PCR and confirmed by RNAse protection assays using a 710 bp anti-sense RNA probe that spanned the alternatively spliced and native P2X4 regions. Injection of full-length, but not alternatively spliced, cRNA into Xenopus oocytes resulted in the expression of ATP gated non-selective cation currents.
Dhulipala
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PD
Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia 19104-6046, USA.
Wang
Y X
YX
Kotlikoff
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MI
D000255:Adenosine Triphosphate / Q000378:metabolism; D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002478:Cells, Cultured; D003001:Cloning, Molecular; D018076:DNA, Complementary; D005753:Gastric Mucosa / Q000378:metabolism; D015870:Gene Expression; D006801:Humans; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D018048:Receptors, Purinergic P2 / Q000235:genetics* / Q000378:metabolism; D058848:Receptors, Purinergic P2X4; D017386:Sequence Homology, Amino Acid; D014982:Xenopus laevis
D018076:DNA, Complementary; C548226:P2RX4 protein, human; C548228:P2rx4 protein, rat; D012333:RNA, Messenger; D018048:Receptors, Purinergic P2; D058848:Receptors, Purinergic P2X4; D000255:Adenosine Triphosphate