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 gamma gene from human islet RNA. A novel cDNA was detected composed of 5' sequence from the human CaM kinase II gamma 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 gammaSRP, 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 gamma gene was previously mapped to human chromosome 10q22, we suggest this novel cDNA may have resulted from trans-splicing.