Resumen de Promoter Choice Determines Splice Site Selection in Protocadherin α and γ Pre-mRNA Splicing

Bosiljka Tasic, Christoph E. Nabholz, Kristin K. Baldwin, Richard Axel, Tom Maniatis

• A family of mammalian protocadherin (Pcdh) proteins is encoded by three closely linked gene clusters (α, β, and γ). Multiple α and γ Pcdh mRNAs are expressed in distinct patterns in the nervous system and are generated by alternative pre-mRNA splicing between different “variable” exons and three “constant” exons within each cluster. We show that each Pcdh variable exon is preceded by a promoter and that promoter choice determines which variable exon is included in a Pcdh mRNA. In addition, we provide evidence that alternative splicing of variable exons within a gene cluster occurs via a cis-splicing mechanism. However, virtually every variable exon can engage in trans-splicing with constant exons from another cluster, albeit at a far lower level.