Distal regulation of alternative splicing by splicing enhancer in equine β-casein intron 1

Abstract

The complexity of cotranscriptional splicing is reflected in the coordinated interplay between various cis-elements and transacting factors. In this report, we demonstrated that a cis-element in intron 1 of the equine b-casein gene (intronic splicing enhancer 1, ISE1) increases the inclusion of all weak exons in its pre-mRNA. The ISE1 also functioned on a hybrid transcript, which was transcribed from the a-globin promoter, where it increased the inclusion of the human fibronectin EDA exon and the b-casein exon 5. The region of ISE1 necessary for its function included the same sequence as is found in some exonic splicing enhancers. Since the ISE1 influenced the splicing of the entire transcript from intron 1, we propose a model for the cotranscriptional splicing of b-casein mRNA, where the 5¢ end of the growing transcript remains associated with the C-terminal domain of RNA polymerase II. Thus, the ISE1 remains in close proximity to the mRNA exit groove throughout transcription and influences all weak exons as soon as they are copied.

Alternative splicing of a single transcription factor drives selfish reproductive behavior in honeybee workers ( Apis mellifera )

“…The 9-bp deletion in A. m. capensis may therefore have far-reaching effects on the splice-site recognition of the upstream laying cassette exon 5. As this was the only consistent sequence difference we found in the four flanking introns of the spliced exons, it might be possible that tae1 not only affects the exon 5 switch but also the splicing of exon 7, as it has been shown that more distant splice regulatory motifs can control splicing of non-neighbor exons (32). Predictions of the secondary structure of intron 5_6 of gemini suggest that this sequence is part of a stem/loop conformation (Mfold) (35).…”

Regulation of Alternative Splicing Through Coupling with Transcription and Chromatin Structure

“…In genes in which multiple alternative exons exist, coordination of splicing events favors some specific combinations over others. Although in many cases alternative splicing events are supposed to occur independently, some specific cases of coordination have been reported www.annualreviews.org • Regulation of Alternative Splicing (62)(63)(64), and a statistical analysis of ESTs (expressed sequence tags) suggests that it might be more common than generally thought (63). Coordination could also arise in posttranscriptional splicing if, for example, different events are regulated by a shared set of splicing factors.…”

Lost in Transcription: Molecular Mechanisms that Control HIV Latency

“…These steps release RNAPII from pausing and reverse negative effects of NELF and DSIF on transcription elongation [25,26,27]. CDK9 phosphorylates serine residues at position 2 (S2) in the CTD of RNAPII, which assures proper co-transcriptional processing of nascent viral transcripts [18,28,29,30,31,32,33]. …”