snRNP U1,U2,U4,U5,U6 are present in the spliceosome but there is no mention of U3.
Are there any cases in which the splicing machinery constructs an mRNA in which the exons are not in the 5' -> 3' genomic order? I'm interested any such cases, whether they involve constitutive or ...
Exons are produced by more than one mechanism, e.g. splicing out introns after transcription, if I remember correctly. Please list all mechanisms.