Splice site selection is a key step that determines the mRNA isoforms generated from a single transcript. The large diversity in splice site sequences emphasizes the plasticity of splice site recognition and selection. In this report, a cell-based reporter system using a SMN1/2 cassette exon was applied to study the roles governing the activation of a cryptic 5'SS from the intron 4 of the CT/CG...

The integrated human immunodeficiency virus type 1 (HIV-1) genome is transcribed in a single pre-mRNA that is alternatively spliced into more than 40 mRNAs. We characterized a novel bidirectional exonic splicing enhancer (ESE) that regulates the expression of the HIV-1 env, vpu, rev, and nef mRNAs. The ESE is localized downstream of the vpu-, env-, and nef-specific 3' splice site no. 5. SF2/ASF...

site cleavage, the spliceosome rearranges to permit exon ligation (Umen and Guthrie, 1995b), the mRNA and lariat products are released (Company et al. Pre-mRNA splicing requires dramatic RNA rearrange-Since this pathway is conserved from yeast to mammals, ments hypothesized to be catalyzed by ATP-depen-it likely reflects fundamental requirements for intron rec-dent RNA unwindases of the DExD/H ...

Intraflagellar transport moves proteins in and out of flagella/cilia and it is essential for the assembly of these organelles. Using whole-genome sequencing, we identified splice site mutations in two IFT genes, IFT81 (fla9) and IFT121 (ift121-2), which lead to flagellar assembly defects in the unicellular green alga Chlamydomonas reinhardtii The splicing defects in these ift mutants are partia...

Predicted single-stranded structure at the 3' splice site is a conserved feature among intervening sequences (IVSs) in eukaryotic nuclear tRNA precursors. The role of 3' splice site structure in splicing was examined through hexanucleotide insertions at a central intron position in the Saccharomyces cerevisiae tRNA gene. These insertions were designed to alter the structure at the splice site w...

MOTIVATION The large amount of available annotated Arabidopsis thaliana sequences allows the induction of splice site prediction models with supervised learning algorithms (see Haussler (1998) for a review and references). These algorithms need information sources or features from which the models can be computed. For splice site prediction, the features we consider in this study are the presen...

The 3' splice site of the influenza A segment 7 transcript is utilized to produce mRNA for the critical M2 ion-channel protein. In solution a 63 nt fragment that includes this region can adopt two conformations: a pseudoknot and a hairpin. In each conformation, the splice site, a binding site for the SF2/ASF exonic splicing enhancer and a polypyrimidine tract, each exists in a different structu...

Pairing between U2 snRNA and the branch site of spliceosomal introns is essential for spliceosome assembly and is thought to be required for the first catalytic step of splicing. We have identified an RNA comprising the 5' end of U2 snRNA and the 3' exon of the ACT1-CUP1 reporter gene, resulting from a trans-splicing reaction in which a 5' splice site-like sequence in the universally conserved ...

Activation of pre-messenger RNA (pre-mRNA) splicing requires 5' splice site recognition by U1 small nuclear RNA (snRNA), which is replaced by U5 and U6 snRNA. Here we use crosslinking to investigate snRNA interactions with the 5' exon adjacent to the 5' splice site, prior to the first step of splicing. U1 snRNA was found to interact with four different 5' exon positions using one specific seque...