Molecular cloning and analysis of Ca2+/calmodulin-dependent protein kinase II from the chicken brain

The goals of this study were to identify specific mRNAs for isoforms of calmodulin-dependent protein kinase II in chicken forebrain, prepare a cDNA expression library, and perform a sequence analysis of the kinase cDNA. Specific mRNAs for α- and β-subunits of the kinase were identified in Northern blots. The mRNA for the α-subunit is larger in the chicken than in the rat, and for the β-subunit is smaller in the chicken than the rat. Nucleotide sequencing of selected clones demonstrated the presence of an α-subunit with a 33 nucleotide insert known as the α-B-isoform. Clones of the β-subunit showed it to contain a deletion of six nucleotides relative to previously described sequences. Variability in the mRNAs of calmodulin kinase II, as shown here, reflect the presence of species-dependent variability in gene structure as well as the presence of different functional isoforms.