Two transcripts and the expression profiles of cyclin A in ovary of the mud crab, Scylla paramamosain

Two transcripts of cyclin A (SPCyA) were identified and characterized from ovaries of the mud crab, Scylla paramamosain. The sequences of the two transcripts contained the same open reading frame and 5 untranslated region (UTR), but differed in 3 UTR. The polyadenylation signals AATAAA were found in the different sites, which might generate alternative polyadenalation and thus the different length of the transcripts. The dendrogram, based on comparison of cyclin A proteins in different species, agreed with the classic taxonomic structure. Reverse transcription-PCR (RT-PCR) showed that the SPCyA mRNA was expressed at the highest level in the ovary. Real-time RT-PCR revealed that the amount of SPCyA mRNA in the ovary increased from the first stage to the fourth stage, then declined at the fifth stage (p<0.05). It implies that SPCyA is closely related to oogonial proliferation (mitosis) and oocyte meiosis.