alter the splicing of Mcl-1 pre-mRNA in mature neuron cultures at both 6 and 24 h post exposures. These results suggest that EtOH exposure can selectively induce alternative splicing of Mcl-1 mRNA in neural progenitors and immature neurons. In order to confirm translation of Mcl-1S mRNA induced by EtOH and possible impact of EtOH on expression of splicing regulatory protein SRSF1 and other members of Bcl-2-associated genes, including Bcl-2, Bax, Bad, and Puma, whole cell protein lysates obtained from hNSPs, hNPCs, immature neurons, and mature neurons exposed to EtOH (50 mM) for 24 h were processed by western blotting (Fig. 4b). Consistent with alternative splicing of Mcl-1S mRNA, EtOH exposure induced Mcl-1S expression in hNSPs, hNPCs, and immature neurons, but not in mature neuron cultures. Interestingly, Mcl-1L expression was quite low in control-untreated cells with slight reduction in their expression in hNSPs and hNPCs and no visible change in immature and mature neurons at 24 h post treatments. These differences in Mcl-1L expression could be related to the differences in its stability or half-life across the cell types. In line with our previous report24, EtOH exposure caused a dramatic reduction in SRSF1 protein levels in hNSPs, hNPCs, and immature neurons.
