A truncated isoform of Ca2+/calmodulin‐dependent protein kinase II expressed in human islets of Langerhans may result from trans‐splicing

Calcium/calmodulin‐dependent protein kinase II (CaM kinase II) has been proposed to play a key role in glucose stimulated insulin secretion. Using the rapid amplification of cDNA ends technique we amplified the 3′ end of the CaM kinase II γ gene from human islet RNA. A novel cDNA was detected composed of 5′ sequence from the human CaM kinase II γ gene joined to the 3′ end of the human signal recognition particle 72 (SRP72) gene. We predict that this mRNA species will code for a truncated form of CaM kinase II, designated γSRP, comprising the entire catalytic and regulatory domains of the protein and with a predicted molecular weight of 37 kDa. We mapped the human SRP72 gene to chromosome 18 and, as the CaM kinase II γ gene was previously mapped to human chromosome 10q22, we suggest this novel cDNA may have resulted from trans‐splicing.