CHARACTERIZATION OF 2 NOVEL HUMAN RETROPSEUDOGENES RELATED TO THE CALMODULIN-ENCODING GENE, CAMII

Two human genomic clones (lambda-hg22 and lambda-hg29), containing two novel calmodulin (CaM) retropseudogenes, were isolated and characterized. The two pseudogenes show high similarity with the human CaMII cDNA, hCE1 [SenGupta et al., J. Biol. Chem. 262 (1987) 16663-16670] and the CaMII-type retropseudogene, hCE2 (CaMII-psi-1) [SenGupta et al., Nucleic Acids Res. 17 (1989) 2868]. One of them, in clone lambda-hg22 (CaMII-psi-2), shows all the characteristics of a processed pseudogene. In clone lambda-hg29 (CaMII-psi-3), however, an Alu repetitive sequence was detected immediately upstream from the ancestral 5'-untranslated region. Downstream from the truncated 3'-untranslated region, three additional copies of Alu repetitive sequences flanking about 750 nucleotides of unknown origin were found. Such a processed retropseudogene flanked by multiple Alu repeats may be a target for further recombination events. The three retropseudogenes CaMII-psi-1, CaMII-psi-2 and CaMII-psi-3 are estimated to be about 49, 21 and 25 million years old, respectively.