sentence: Taken together these data suggest that rapamycin alters the stability of PTC-containing isoforms in polyribosome complexes rather than the AS of their pre-mRNA.We further assayed the abundance of PTC-containing and non PTC isoforms of SRSF6 and CCAR1 in total and polyribosome-bound mRNA fractions at 7 h post-rapamycin stimulation .