HUMAN GAP JUNCTION PROTEIN CONNEXIN31 - MOLECULAR-CLONING AND EXPRESSION ANALYSIS

We have isolated and characterized a human genomic clone containing th e complete coding region of connexin31 (Cx31). Similar to rodent Cx31, the coding region of human Cx31 is completely contained within the se cond exon and consists of 810 nucleotides. The deduced human Cx31 poly peptide consists of 270 amino acids with a predicted molecular mass of 30.818 kDa. Its sequence is most similar to mouse Cx31 (82.6% identic al amino acids) and rat (83.0% identical amino acids), but shows consi derably fewer potential sites of phosphorylation. After Northern blot hybridization, two Cx31 transcripts of 2.2 and 1.8 kb were detected in total RNA of the human keratinocyte cell line HaCaT and two transcrip ts of 2.2 and 1.9 kb in total RNA of E6/E7 transfected human keratinoc ytes (HEK cells). Using affinity-purified rabbit antibodies to mouse C x31, immunofluorescence analysis demonstrated relatively weak expressi on of human Cx31 in HaCaT and HEK cells. The Cx31 gene exists as a sin gle copy gene in the human genome and was mapped to the chromosomal re gion 1p34-p36 by analyzing human-mouse somatic cell hybrids. (C) 1998 Academic Press.