Antagonistic factors control the unproductive splicing of SC35 terminal intron

Natacha Dreumont (1) , Sara Hardy (1) , Isabelle Behm-Ansmant (2) , Liliane Kister (1) , Christiane Branlant (2) , James Stevenin (1) , Cyril Bourgeois (1)

1 IGBMC - Institut de Génétique et de Biologie Moléculaire et Cellulaire
2 AREMS - ARN-RNP, structure-fonction-maturation

Alternative splicing is regulated in part by variations in the relative concentrations of a variety of factors, including serine/arginine-rich (SR) proteins. The SR protein SC35 self-regulates its expression by stimulating unproductive splicing events in the 3 0 untranslated region of its own pre-mRNA. Using various minigene constructs containing the terminal retained intron and flanking exons, we identified in the highly conserved last exon a number of exonic splicing enhancer elements responding specifically to SC35, and showed an inverse correlation between affinity of SC35 and enhancer strength. The enhancer region, which is included in a long stem loop, also contains repressor elements, and is recognized by other RNA-binding proteins, notably hnRNP H protein and TAR DNA binding protein (TDP-43). Finally, in vitro and in cellulo experiments indicated that hnRNP H and TDP-43 antagonize the binding of SC35 to the terminal exon and specifically repress the use of SC35 terminal 3 0 splice site. Our study provides new information about the molecular mechanisms of SC35-mediated splicing activation. It also highlights the existence of a complex network of self-and cross-regulatory mechanisms between splicing regulators, which controls their homeostasis and offers many ways of modulating their concentration in response to the cellular environment.

Domaines: Biologie moléculaire

Natacha Dreumont, Sara Hardy, Isabelle Behm-Ansmant, Liliane Kister, Christiane Branlant, et al.. Antagonistic factors control the unproductive splicing of SC35 terminal intron. Nucleic Acids Research, 2010, 38 (4), pp.1353 - 1366. ⟨10.1093/nar/gkp1086⟩. ⟨hal-01738427⟩