Cloning and in vitro translation of a human calmodulin 2 cDNA

Abstract

During construction of a human full-length cDNA bank, we have cloned a cDNA encoding calmodulin from the human lymphoma U937 cDNA library. A database search suggests that this cDNA encodes full-length calmodulin 2 that has longest 5′ noncoding region. To examine the Ca2+-dependent binding ability of calmodulin encoded from the cDNA, it was in vitro translated in a rabbit reticulocyte lysate containing [35S] methionine and its product was mixed with 3′, 5′-cyclic nucleotide phosphodiesterase. Electrophoretic analysis on a native polyacrylamide gel revealed that the in vitro translated product of this cDNA can bind to 3′, 5′-cyclic nucleotide phosphodiesterase in the Ca2+-dependent manner. This result indicates that the in vitro translation product of the calmodulin cDNA, [35S] labeled calomodulin, can be used as a probe to assess the calmodulin-binding ability of a target protein or to screen the calmodulin binding proteins.