Identification of four alternatively spliced isoforms of chicken casein kinase I alpha that are all expressed in diverse cell types.
Casein kinase I (CKI) is a family of widely expressed protein kinases. It is previously shown in mammalian tissues that CKIalpha exists as two or three alternatively spliced isoforms (Rowles et al.,1991; Zhang et al., 1996; Kuret et al., 1997). We now report that four alternatively spliced isoforms of CKIalpha are expressed in many chicken cells and tissues. A partial cDNA clone was isolated from a chicken brain library, using a probe derived from a bovine CKIalpha cDNA. The translated sequence of this clone was 100% identical to the bovine homolog containing the 'L' insert, with the addition of 12 amino acids just before the C terminus that had previously been reported in human and Xenopus CKIalpa. After completing the missing portion of the coding sequence by 5' RACE (rapid amplification of cDNA ends), full-length cDNA was PCR amplified from chicken brain cDNA, yielding four different products. These were cloned and sequenced and found to correspond to the four CKIalpha isoforms: CKIalpha, CKIalphaL, CKIalphaS and CKILalphaLS, where 'S' is the insert consisting of the 12 human/Xenopus C-terminal amino acids. Using reverse transcription and polymerase chain reaction (Rt-PCR), it was shown that the four isoforms are all expressed in neurons, fibroblasts and several tissues. This represents the first demonstration that four splice variants exist and are all expressed in a single type of cell.
Department of Anatomy and Cell Biology, University of Florida College of Medicine, Gainsville, FL 32610, USA.
C L
CL
Green
G S
GS
Bennett
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015139:Blotting, Southern; D001921:Brain / Q000166:cytology / Q000201:enzymology; D047388:Casein Kinases; D002645:Chickens / Q000235:genetics*; D004247:DNA / Q000032:analysis / Q000235:genetics; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D005057:Eukaryotic Cells / Q000166:cytology / Q000201:enzymology*; D005347:Fibroblasts / Q000166:cytology / Q000201:enzymology; D015870:Gene Expression / Q000235:genetics; D007527:Isoenzymes / Q000235:genetics*; D008969:Molecular Sequence Data; D009474:Neurons / Q000166:cytology / Q000201:enzymology; D016366:Open Reading Frames / Q000235:genetics; D011494:Protein Kinases / Q000235:genetics*; D012313:RNA / Q000032:analysis / Q000235:genetics; D017422:Sequence Analysis, DNA; D014018:Tissue Distribution; D014158:Transcription, Genetic / Q000235:genetics
D018076:DNA, Complementary; D007527:Isoenzymes; D012313:RNA; D004247:DNA; D011494:Protein Kinases; D047388:Casein Kinases