Reptin52 expression during in vitro neural differentiation of human embryonic stem cells

Human embryonic stem cells (hESCs) give rise to all somatic cell types, including neural cells such as astrocytes, oligodendrocytes and neurons. Commitment of hESC to a neural fate can be achieved via selection and expansion of developing neural stem cells, which, grown into non-adhering colonies called neurospheres, express nestin, a neurofilament marker. Analysis of hESC and hESC-derived neural stem cell nuclear extracts revealed an increased expression of Reptin52 in neurosphere nuclei. The increase in Reptin52 was evident throughout directed neuronal differentiation as assessed by western blotting, quantitative RT-PCR and immunocytochemistry. Reptin52 serves a pivotal regulatory role in nuclear activities such as transcription regulation and histone modification. In that regard, co-immunoprecipitation experiments showed that binding partners of Reptin52 (Pontin52, beta-catenin and ATF-2) associate with this regulatory protein in hESC-derived neuronal precursors. Moreover, expression of two of these proteins (beta-catenin - the end product of the Wnt signaling pathway - and ATF-2) is coordinately regulated with Reptin52.