Molecular cloning and sequence analyses of calcium/calmodulin- dependent protein kinase II from fetal and adult human brain – Sequence analyses of human brain calcium/calmodulin-dependent protein kinase II

Abstract

The aims of this study were to characterize specific mRNAs and the expression pattern for isoforms of calcium/calmodulin-dependent protein kinase II (CaMKII) in the human brain. We cloned and sequenced the CaMKII α and β subunit cDNAs, and used them to study the CaMKII expression in human brain. Four distinct isoforms of CAMKII were isolated. Two of them were characterized as CaMKII α and β subunits. The other two showed similar nucleotide sequences, but one had a 33-bp insertion relative to the α subunit, and the other had a 75-bp deletion relative to the β subunit. These alterations are located within the variable regions. These two isoforms were characterized as CaMKII α_B and β_e. Northern blot analysis showed that a 4.4-kb messenger RNA for the α isoform and a 3.9-kb messenger RNA for the β isoform were expressed in both human fetal and adult brain to different degrees. The results indicate that CaMKII expression is developmentally regulated. The CaMKII isoform expression was confirmed in human fetal and adult brain using RT-PCR with specific primers, which flanked the CaMKII variable regions. The CaMKII α, α_B, β, β′ and β_e isoforms were characterized in both human fetal and adult brain.