P68 RNA helicase (DDX5) alters activity of cis- and trans-acting factors of the alternative splicing of H-Ras.
BACKGROUND
H-Ras pre-mRNA undergoes an alternative splicing process to render two proteins, namely p21 H-Ras and p19 H-Ras, due to either the exclusion or inclusion of the alternative intron D exon (IDX), respectively. p68 RNA helicase (p68) is known to reduce IDX inclusion.


RESULTS
Here we show that p68 unwinds the stem-loop IDX-rasISS1 structure and prevents binding of hnRNP H to IDX-rasISS1. We also found that p68 alters the dynamic localization of SC35, a splicing factor that promotes IDX inclusion. The knockdown of hnRNP A1, FUS/TLS and hnRNP H resulted in upregulation of the expression of the gene encoding the SC35-binding protein, SFRS2IP. Finally, FUS/TLS was observed to upregulate p19 expression and to stimulate IDX inclusion, and in vivo RNAi-mediated depletion of hnRNP H decreased p19 H-Ras abundance.


CONCLUSIONS
Taken together, p68 is shown to be an essential player in the regulation of H-Ras expression as well as in a vital transduction signal pathway tied to cell proliferation and many cancer processes.
Camats
Maria
M
Unidad de Splicing, Instituto de Investigaciones Biomédicas de Barcelona-Consejo Superior de Investigaciones Científicas, Barcelona, Spain.
Guil
Sonia
S
Kokolo
Mariette
M
Bach-Elias
Montse
M
D017398:Alternative Splicing; D001483:Base Sequence; D002455:Cell Division / Q000235:genetics; D053487:DEAD-box RNA Helicases / Q000378:metabolism*; D011905:Genes, ras; D017506:H(+)-K(+)-Exchanging ATPase / Q000378:metabolism; D034441:Heterogeneous-Nuclear Ribonucleoproteins / Q000235:genetics / Q000378:metabolism; D007700:Kinetics; D008969:Molecular Sequence Data; D012322:RNA Precursors / Q000235:genetics
D034441:Heterogeneous-Nuclear Ribonucleoproteins; D012322:RNA Precursors; D017506:H(+)-K(+)-Exchanging ATPase; D053487:DEAD-box RNA Helicases