To gain insight into possible impact of EtOH on alternative splicing of Mcl-1, alternative splicing of Mcl-1 pre-mRNA was further analyzed in different lineages of neuronal cells. The cultures of hNSPs, hNPCs, immature neurons, and mature neurons were exposed to EtOH (50 mM) for 6 and 24 h. Total RNA from cells was isolated and analyzed by RT-PCR for amplification and detection of Mcl-1 long and short isoforms. The antiapoptotic isoform Mcl-1L is expressed in hNSPs, hNPCs, immature neurons, and mature neurons (Fig. 4a). Interestingly, consistent with cell viability and apoptosis assays (Figs. 2 and 3, respectively), proapoptotic isoform Mcl-1S is only induced in neuronal progenitors and immature neurons at 6 and 24 h post exposures (Fig. 4a). On the other hand, induction of Mcl-1S isoform in hNSPs was only observed at 24 h post exposures. EtOH exposure did not 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
