Abstract: Objective To explore the biological function of RNA binding protein heterogeneous nuclear ribonucleoprotein A3(hnRNPA3) in the maintenance of pluripotency of human embryonic stem cells(hESCs) and to reveal its new mechanism in RNA transport. Methods The interaction of hnRNPA3 with nuclear pore and localization were examined by immunoprecipitation of nuclear pore complex and cytoplasmic separation in hESCs. After inhibiting the endogenous expression of hnRNPA3, the expression of the pluripotency/differentiation marker genes was detected by qPCR, and the effect on the nucleoplasmic distribution of polyA⁺ RNA and OCT4 mRNA was tested by RNA fluorescence in situ hybridization to predict the binding of hnRNPA3 to known RNA export associated proteins. Results hnRNPA3 was localized in the nucleus and interacted with the nuclear pore. Inhibiting the endogenous expression of hnRNPA3 significantly inhibited the cloning-formation ability of hESC(P＜0.05) and resulted in the increase of the expression of cell differentiation markers(P＜0.001) and significantly inhibited the export of polyA⁺ RNA as well as OCT4 mRNA(P＜0.001). The protein interaction network predicted that hnRNPA3 may bind to about one-third of the known RNA export associated proteins. Conclusions hnRNPA3 regulates hESC pluripotency by impacting on mRNA export.

Key words: human embryonic stem cells, hnRNPA3, pluripotency and self-renewal, mRNA transport