Stimulatory roles of epidermal growth factor receptor (EGFR) in ovarian development of mud crab Scylla paramamosain

Abstract

The epidermal growth factor receptor (EGFR) is a pleiotropic glycoprotein which plays a role in regulating cell proliferation, migration and differentiation. However, to date little is known about its functions in crustaceans. In this study, we successfully identified SpEGFR from mud crab Scylla paramamosain. RT-PCR result showed that SpEGFR was widely distributed in all tested tissues and highly expressed in ovary. In situ hybridization revealed that SpEGFR mainly localized in oocyte perinuclear region with notably obvious signals. In vitro experiments showed that the expression of SpVgR and SpCyclin B in ovary explants from late vitellogenic stage crabs (summer) were significantly increased when treated with 1 nM human EGF (hEGF) for 1 h, while there was no obvious change towards SpEGFR. Interestingly, as for winter crab at the same vitellogenic stage, the expression of SpVgR and SpCyclin B in ovary explants did not show significant increase until treated with higher concentration of 10 nM hEGF and longer incubation time of 12 h. In addition, the hEGF-induced effect could be suppressed by pre-treated with EGFR inhibitor AG1478 and PD153035, respectively, which further indicated that EGF-EGFR pathway played a vital role in ovarian development in mud crab. In conclusion, SpEGFR might promote ovarian development by stimulating the expression of SpVgR and SpCyclin B under hEGF-induced treatment. The different physiological response to hEGF in the same vitellogenic stage crabs between summer and winter might be attributed to the changes in metabolism and physiological sensitivity.