FIG. 3.

RT-PCR analysis of splicing of NRS mutants. (A) Diagram of the splicing reporter construct and the normally and cryptically spliced products observed. The numbers on the right represent transcript lengths (in base pairs). (B) RT-PCR products were generated from RNA isolated from transfected cells using primers in the exons as shown in panel A. (C) Sequencing of cryptic products revealed that both used the NRS U1 binding site as a 5′ splice site. The 389-bp product also had an upstream intron of 313 nt, extending from the myc 5′ splice site, as shown in panel A.