Molecular cloning, expression, and chromosomal mapping of the porcine CDC-2-like kinase 1 (CLK1) gene

CDC-2-like kinase 1 (CLK1) plays a critical role in regulating pre-RNA splicing and post-transcriptional gene expression. Two distinct transcripts of the porcine CLK1 gene, known as full-length CLK1 and truncated CLK1 (CLK1 ( T )), were identified by in silico cloning, RT-PCR, and RACE. The entire cDNA sequence of full-length CLK1 was 1771 bp, containing a 1455 bp ORF encoding a deduced protein of 484 amino acids. The complete cDNA sequence of CLK1 ( T ) is 1680 bp, containing a 414 bp ORF encoding a deduced protein of 137 amino acids. The genomic structure and sequence of porcine CLK1 were analyzed using a bacterial artificial chromosome clone of a Chinese Erhualian pig, with 13 exons and 12 introns spanning approximately 9 kb. RT-PCR revealed that the full-length and truncated splice forms were expressed at equivalent levels in pig heart, fat, liver, spleen, and lymph tissues. The full-length splice form was expressed at a much higher level than the truncated form in tissues of the pig cerebrum, longissimus dorsi, small intestine, and kidney. The CLK1 gene was physically assigned to SSC 15 between microsatellite markers SW1316 and SW2083 using the IMpRH panels.