Exon/intron structure and alternative transcripts of the CUTL1 gene

The human CUTL1 gene (Cut-like 1) is a candidate tumor suppressor gene loca ted on chromosome 7 at band 22, a region that is frequently deleted in seve ral human cancers. The gene spans at least 340 kb and contains 33 exons. Sy nthesis of five different transcripts involves two promoter regions, two po lyadenylation sites and seven alternative splicing events. The two polyaden ylation sites are located at the ends of exons 24 and 33 and are separated by approximately 40 kb. Transcription is initiated in two genomic regions, giving rise to alternate first exons which are spliced to a common exon 2. All transcripts contain exons 2 to 14, but differ in their 3' regions. Exon 14 can be spliced alternatively to the beginning or the middle of exon 15, or to exon 25, generating transcripts with exons 15 to 24 or exons 25 to 3 3. Moreover, exon 16 can be spliced out from the mature transcripts that co ntain exons 15 to 24. Overall, five distinct transcripts are generated as a result of alternative transcription initiation, splicing and polyadenylati on, We discuss potential mechanisms by which alternate polyadenylation site usage may affect alternative splicing events and vice versa. (C) 2000 Else vier Science B.V. All rights reserved.