Biochemical and Biophysical Research Communications vol:215 issue:2 pages:666-73
Two types of PP2A catalytic subunit cDNA clones were isolated from a Xenopus oocyte library. One type corresponds to the Xenopus C36 alpha (XC36 alpha) isoform as published by Cormier et al. (1991) and another type encodes for a novel isoform of PP2AC36 (XC36 beta), more homologous to the C36 beta isoform cloned from Mammalia. Northern blot analysis with isoform specific probes showed that the XC36 alpha mRNA transcript of 2 kb is more abundant than the XC36 beta mRNA of 1.9 kb during embryogenesis and in adult tissues. Both transcripts are highly expressed in ovary and heart relative to the other adult tissues examined. The high expression levels of both XC36 alpha and XC36 beta transcripts in the ovary decrease during the first mitotic embryonic divisions. Resumption of zygotic expression starts at about the same time for both mRNAs, during the tailbud stage, but the XC36 beta transcript shows only a moderate and transient increase and declines again during the tadpole stage whereas expression of XC36 alpha increases further during the same period until the onset of metamorphosis.