New paper from Alberto Kornblihtt's group and a press article

Congratulations to Alberto Kornblihtt and his group on the publication of their newest paper:

Control of alternative splicing through siRNA-mediated transcriptional gene silencing.
Alló M, Buggiano V, Fededa JP, Petrillo E, Schor I, de la Mata M, Agirre E, Plass M, Eyras E, Elela SA, Klinck R, Chabot B, Kornblihtt AR.
Nat Struct Mol Biol. 2009 Jun 21.

Abstract: When targeting promoter regions, small interfering RNAs (siRNAs) trigger a previously proposed pathway known as transcriptional gene silencing by promoting heterochromatin formation. Here we show that siRNAs targeting intronic or exonic sequences close to an alternative exon regulate the splicing of that exon. The effect occurred in hepatoma and HeLa cells with siRNA antisense strands designed to enter the silencing pathway, suggesting hybridization with nascent pre-mRNA. Unexpectedly,
in HeLa cells the sense strands were also effective, suggesting that an endogenous antisense transcript, detectable in HeLa but not in hepatoma cells, acts as a target. The effect depends on Argonaute-1 and is counterbalanced by factors favoring chromatin opening or transcriptional elongation. The increase in heterochromatin marks (dimethylation at Lys9 and trimethylation at Lys27 of histone H3) at the target site, the need for the heterochromatin-associated protein HP1a and the reduction in RNA polymerase II processivity suggest a mechanism involving the kinetic coupling of transcription and alternative splicing.

You can also read a press article (in Spanish) about Alberto's research and the collaboration with Eduardo Eyras' group that appeared in "Clarín" on the 28th of June. "Clarín" is the most distributed newspaper in Argentina with 760.000 copies being sold on Sundays.