RT-PCR analysis of LMAN1 mRNA from probands of families B7 and B16. (A) Schematics of the LMAN1 cDNA with locations of PCR primers (Table 2, a-g) indicated. (B) Agarose gel electrophoresis of the RT-PCR products after amplification of LMAN1 mRNA with the various primer combinations indicated. The bottom bands in B16/b+f and B16/c+f lanes represent alternatively spliced species with exon 8 skipping, whereas the top bands represent the normally spliced products. The 900-bp band in the B16/b+f lane was a nonspecific PCR product according to sequence analysis. Two specific PCR products were observed in the B7/a+d lane. Sequencing of the latter PCR products further amplified by nested PCR revealed that the top band represents the normal spliced product, whereas the bottom band represents an alternatively spliced species with exon 4 skipping. Amplification of the coding region of MCFD2 mRNA served as a control for RNA quality.