Identification and characterization of human neuronal voltage-gated calcium channel gamma 3 subunit gene

By homologous expressed sequence tag (EST) searching, one EST (GenBank: W29095) was obtained, which shows 75% identity in 435 bp overlap with the coding sequence of mouse Cacng2 gene. A 1 545 bp cDNA fragment was obtained from the nested polymerase chain reaction (PCR) and rapid applification of cDNA end (RACE) reaction in the human brain prefrontal cortex cDNA library and the human brain Ready cDNA with the primers designed on W29095. The fragment contained a 948-bp open reading frame (ORF) encoding 315 amino acids, and was named CACNG3. As it was identical to a BAC clone (GenBank: AC004125) from chromosome 16p12-p13.1, the CACNG3 gene was mapped to human chromosome 16p12-p13.1, and the coding region was composed of 4 exons. Reverse transcription PCR (RT-PCR) analysis showed that the CACNG3 gene expressed in human adult brain and fetal brain. Single strand comformation polymorphism (SSCP) analysis was performed in 3 pedigrees with autosomal recessive retinitis pigmentosa, 8 pedigrees with autosomal recessive retinitis pigmentosa accompanied by deafness and 2 pedigrees with epilepsy, but no mutation was detected.