RT-PCR analysis of alternatively spliced ICAM-1 RNA isoforms.

RT-PCR was performed on spleen RNA from wild-type and ICAM-1 mutant mice using 5′UTR and 3′UTR primers. (A) RT-PCR products resolved on a 1.5% agarose gel. For identification, fragments were transferred to a nitrocellulose membrane, which was hybridized with an exon 2-specific probe. Positive fragments were cloned and sequenced. Indicated on the diagram are short sequences of the exons joining the alternatively spliced sites. (B) Schematic representation of the ICAM-1 isoforms of ICAM-1–exon 4 mutant mice. The isoforms contain 2 or 3 extracellular domains, a transmembrane domain, and a cytoplasmic region.