Cloning of cyclin E cDNA of the sea urchin, Hemicentrotus pulcherrimus.

cDNA encoding maternal cyclin E (HpCycE) has been cloned from the oocyte cDNA library of the sea urchin, Hemicentrotus pulcherrimus, by differential screening with a cDNA probe covering the total poly(A)(+) RNAs of 16 cell-stage embryos and gastrulae. In this communication we describe similarity of amino acid sequences between HpCycE and those of cyclin E from other organisms and maternal origin of HpCycE. The amino acid sequence deduced from the nucleotide sequence of HpCycE cDNA is highly similar to those of human, rat, chicken, Xenopus, zebrafish and Drosophila, while its similarity to other cyclins is much lower. A gene for HpCycE exists as a single copy in the genome of H. pulcherrimus. Northern blotting revealed that the mRNA for HpCycE is maintained at a high level up to the morula stage and thereafter declines.