Multiple mRNA species code for the catalytic subunit of the cAMP-dependent protein kinase from LLC-PK1 cells. Evidence for two forms of the catalytic subunit.
We present evidence for the existence of two forms of the catalytic (C) subunit of the cAMP-dependent protein kinase. A lambda gt-11 cDNA library constructed from poly(A)-rich RNA from the porcine kidney cell line, LLC-PK1, was screened using a 1.5-kb EcoRI fragment from a bovine cDNA for the C subunit. Two independent classes of cDNAs were identified on the basis of partial restriction map and sequence data. These two cDNAs, lambda CAT4 and lambda CAT3, apparently encode two forms of C subunit designated C alpha and C beta, respectively. The nucleotide sequence of the C alpha and C beta cDNAs revealed differences in the coding region and particularly in the 3' untranslated region. However, the deducted amino acid sequences of C alpha and C beta subunits were 96% homologous to the sequences so far determined. Specific probes from the 3' coding region of the two cDNA species were used to investigate C subunit mRNA expression in LLC-PK1 cells. Northern analysis showed a major mRNA species of 2.8 kb with the C alpha probe while the C beta probe detected two mRNA species of 5.0 kb and 3.8 kb. These data were supported by genomic blot analysis which showed distinct hybridization patterns with either the C alpha or C beta probes. All the available evidence suggests that at least two distinct genes encode the C subunit which are expressed in LLC-PK1 cells.
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D004247:DNA / Q000302:isolation & purification; D005786:Gene Expression Regulation; D007668:Kidney / Q000032:analysis; D011061:Poly A / Q000032:analysis; D011494:Protein Kinases / Q000235:genetics*; D012313:RNA / Q000032:analysis; D012333:RNA, Messenger / Q000032:analysis*; D013552:Swine
D012333:RNA, Messenger; D011061:Poly A; D012313:RNA; D004247:DNA; D011494:Protein Kinases