Cloning and differential expression of new calcium, calmodulin-dependent protein kinase II isoforms in Xenopus laevis oocytes and several adult tissues

The different oligomers composing the high molecular weight calcium/calmodu lin-dependent protein kinase II (CaMKII) holoenzyme, previously shown to be transiently activated during Xenopus oocyte maturation, migrate on SDS-PAG E as proteins of 83, 72, 62, 56, and 52 kDa and have all been cloned. The h oloenzyme consists of the CaMKII isoforms gammaB, gammaC, and delta 12, alr eady described in other species, while gammaJ, gammaK, gammaL, gammaM, and gammaN are now described for the first time. The gamma -isoforms are splice variants of the I gene, containing in their variable region different comb inations of known exons and one, two or three novel exons, Semi-quantitativ e RT-PCR revealed that all isoforms identified in prophase oocytes are also expressed in adult tissues with a tissue-specific expression pattern, At l east thirty different CaMKII isoforms could be identified in different Xeno pus adult tissues, most of which are described here for the first time.