Somatic misexpression of germline P granules and enhanced RNA interference in retinoblastoma pathway mutants

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Abstract

Caenorhabditis elegans homologues of the retinoblastoma (Rb) tumour suppressor complex specify cell lineage during development1,2. Here we show that mutations in Rb pathway components enhance RNA interference (RNAi) and cause somatic cells to express genes and elaborate perinuclear structures normally limited to germline-specific P granules. Furthermore, particular gene inactivations that disrupt RNAi reverse the cell lineage transformations of Rb pathway mutants. These findings suggest that mutations in Rb pathway components cause cells to revert to patterns of gene expression normally restricted to germ cells. Rb may act by a similar mechanism to transform mammalian cells.

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Figure 1: Rb pathway mutants are more sensitive to RNAi than wild-type animals.
Figure 2: Mutations in the Rb pathway cause soma to germline transformation and transgene silencing.
Figure 3: Inactivation of six RNAi factors suppresses the multiple vulvae phenotype of the Rb pathway mutants.

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Acknowledgements

We thank E. C. Andersen, W. G. Kelly, N. Dyson and V. Reineke for discussions; T. Sijen for reagents; H. Y. Mak for the unpublished tub-1::gfp transgene; J. Ahringer and M. Vidal for the feeding RNAi bacteria clones; S. Fischer for constructing the hand-picked RNAi library; S. Strome for the anti-PGL-1 antibodies; and E. C. Andersen, H. R. Horvitz, C. P. Hunter, F. Palladino, the Caenorhabditis Genetics Center and C. elegans Gene Knockout Consortium for some of the strains.Author Contributions D.W. conducted experiments and analysed data for all figures and tables, except for Figs 2a and 3b; S.K. made the initial observation of enhanced RNAi in lin-15 and synergistic enhancement of RNAi in eri-1; lin-15; D.C. did immunofluorescence staining of PGL-1 in Figs 1a and 3b; J.K.K., H.W.G. and R.S.K. identified 36 RNAi-defective genes that were tested by D.W. for their interaction with the Rb pathway; C.C.M. and G.R. were principal investigators.

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Correspondence to Gary Ruvkun.

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Reprints and permissions information is available at npg.nature.com/reprintsandpermissions. The authors declare no competing financial interests.

Supplementary information

Supplementary Methods

Additional descriptions of methods used in this study. (PDF 17 kb)

Supplemenetary Table S1

The enhanced RNAi, but not the cell lineage defects, of Rb pathway mutants requires the canonical RNAi pathway. (PDF 41 kb)

Supplementary Table S2

Mutation in lin-15B releases the requirement of RNAi for the RNA-dependent RNA polymerase RRF-1. (PDF 9 kb)

Supplementary Figure S1 (PDF 2557 kb)

Supplementary Figure S2 (PDF 152 kb)

Supplementary Figure S3 (PDF 206 kb)

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Wang, D., Kennedy, S., Conte, D. et al. Somatic misexpression of germline P granules and enhanced RNA interference in retinoblastoma pathway mutants. Nature 436, 593–597 (2005) doi:10.1038/nature04010

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