Figure 3.

The conservation of NCoR2 exon 37 alternative splicing. NCoR2 exon 37 in Xenopus and mouse has two splice donors (red bars), site 1 is internal and site 2 is at the end of the extended exon. Exon 37b, between the two sites, encodes the CoRNR box 1 motif. (a) The potential site 1 GT splice donor is present in at least one representative of each vertebrate group and when present is part of a high-scoring consensus. A site 1 GT is present in the sea squirt, but is part of a poor consensus splice donor. (b) RT-PCR analysis of exon 37 alternative splicing across a range of species. The size of the PCR product generated from lamprey cDNA indicates that it includes exon 37b while that from 48 h zebrafish embryos corresponds predominantly to 37b–transcripts. Xenopus, in contrast, generates both isoforms as shown by the two bands in the RT-PCR.