Relative expression of proprotein convertases in rat ovaries during pregnancy

BACKGROUND: Proprotein convertases are a family of serine proteinases that are related to bacterial subtilisin and yeast kexin. They are involved in posttranslational processing of the precursors of a vast number of cellular proteins. With the exception of PC1/3, the relative expression levels of the proprotein convertases in the ovary during pregnancy have not been reported. The purpose of this study is to determine by real-time PCR the relative expression levels of all nine proprotein convertases in rat ovaries during pregnancy and at 3 days postpartum. METHODS: RNA was extracted from ovaries at Day 0, 4, 9, 11, 13, 15, 18, and 20 of pregnancy as well as 3 days postpartum. Relative expression levels of Pcsk1, Pcsk2, Furin, Pcsk4, Pcsk5, Pcsk6, Pcsk7, Mbtps1 and Pcsk9 were determined with real-time PCR. Results were reported as fold-change over the level at Day 0 of pregnancy. RESULTS: Results showed that Pcsk1 and Pcsk6 were upregulated as gestation advanced, in parallel with an observed increase in relaxin transcript. Pcsk2 showed downregulation as gestation advanced, while Pcsk5 showed relatively higher levels in early pregnancy and postpartum, but lower level in mid-pregnancy. On the other hand, Furin, Pcsk4, Pcsk7, Mbtps1 and Pcsk9 showed little change of expression throughout gestation. CONCLUSION: PC1/3 (PCSK1) and PACE4 (PCSK6) may play an important role in proprotein processing in the ovary during late pregnancy.