Tandem alternative splicing of zebrafish connexin45.6.
Early studies suggested that most connexin genes share a relatively simple structure with a single intron of variable length interrupting the 5' untranslated region (UTR). Here we report that zebrafish cx45.6 shows six isoforms of alternative 5'UTRs which are generated from multiple promoter usage and alternative pre-mRNA splicing. Interestingly, cx45.6 undergoes tandem alternative splicing, which produces transcripts only differing by 3 nucleotides. This is the first study that has demonstrated tandem alternative pre-mRNA splicing in the connexin gene family. Expression patterns of cx45.6 alternative transcripts were demonstrated by real-time RT-PCR during zebrafish embryonic development and in adult tissues. The complexity of 5'UTR diversity suggests complicated regulatory mechanisms for cx45.6 gene expression at both transcriptional and post-transcriptional levels, and we propose that tandem alternative splicing in cx45.6 5'UTRs could play a role in translational control. These results lay groundwork for further investigations on the regulation and function of cx45.6 gene expression.
Tao
Liang
L
Department of Biological Sciences, University of Manitoba, Winnipeg, Canada. tao@cc.umanitoba.ca
Valdimarsson
Gunnar
G
D020121:5' Untranslated Regions / Q000235:genetics; D017398:Alternative Splicing / Q000235:genetics*; D000818:Animals; D001483:Base Sequence; D017630:Connexins / Q000235:genetics* / Q000378:metabolism; D017931:DNA Primers / Q000235:genetics; D040461:Gene Components; D005786:Gene Expression Regulation / Q000235:genetics*; D008969:Molecular Sequence Data; D020033:Protein Isoforms / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D015027:Zebrafish / Q000235:genetics*; D029961:Zebrafish Proteins / Q000235:genetics* / Q000378:metabolism
D020121:5' Untranslated Regions; D017630:Connexins; D017931:DNA Primers; D020033:Protein Isoforms; D029961:Zebrafish Proteins; C485241:connexin 45.6, zebrafish