-2 causes alterations in mRNA processing. (A) Northern blot analysis of total RNA isolated from HEK 293 T cells transfected with wild type or mutant pNL4-3 was isolated 48 h post transfection. RNA was separated on a 1% RNA agarose gel, capillary blotted, and cross-linked on a positively charged nylon membrane and UV cross-linked. The membrane was treated with a DIG-labelled DNA fragment binding to exon 7. (B) Quantitation of relative amounts of mRNAs from (A). (C) RNA from panel A was subjected to quantitative RT-PCR analysis using a primer pair specific for intron 1 containing mRNAs of the 9 kb mRNA class (#3389/#3390), and intronless mRNAs of the 2 kb class (#3391/#3392), which were normalized to exon 7 containing mRNAs (#3387/#3388).