Large-scale RNAi screens identify novel genes that interact with the C. elegans retinoblastoma pathway as well as splicing-related components with synMuv B activity.
BACKGROUND
The retinoblastoma tumor suppressor (Rb) acts in a conserved pathway that is deregulated in most human cancers. Inactivation of the single Rb-related gene in Caenorhabditis elegans, lin-35, has only limited effects on viability and fertility, yet causes changes in cell-fate and cell-cycle regulation when combined with inactivation of specific other genes. For instance, lin-35 Rb is a synthetic multivulva (synMuv) class B gene, which causes a multivulva phenotype when inactivated simultaneously with a class A or C synMuv gene.


RESULTS
We used the ORFeome RNAi library to identify genes that interact with C. elegans lin-35 Rb and identified 57 genes that showed synthetic or enhanced RNAi phenotypes in lin-35 mutants as compared to rrf-3 and eri-1 RNAi hypersensitive mutants. Based on characterizations of a deletion allele, the synthetic lin-35 interactor zfp-2 was found to suppress RNAi and to cooperate with lin-35 Rb in somatic gonad development. Interestingly, ten splicing-related genes were found to function similar to lin-35 Rb, as synMuv B genes that prevent inappropriate vulval induction. Partial inactivation of specific spliceosome components revealed further similarities with lin-35 Rb functions in cell-cycle control, transgene expression and restricted expression of germline granules.


CONCLUSIONS
We identified an extensive series of candidate lin-35 Rb interacting genes and validated zfp-2 as a novel lin-35 synthetic lethal gene. In addition, we observed a novel role for a subset of splicing components in lin-35 Rb-controlled processes. Our data support novel hypotheses about possibilities for anti-cancer therapies and multilevel regulation of gene expression.
Ceron
Julian
J
Massachusetts General Hospital Cancer Center and Harvard Medical School, Charlestown, MA 02129, USA. jceron@ir.vhebron.net
Rual
Jean-François
JF
Chandra
Abha
A
Dupuy
Denis
D
Vidal
Marc
M
van den Heuvel
Sander
S
D000818:Animals; D017173:Caenorhabditis elegans / Q000235:genetics* / Q000254:growth & development; D029742:Caenorhabditis elegans Proteins / Q000235:genetics*; D005260:Female; D018507:Gene Expression Regulation, Developmental; D017238:Genes, Helminth; D010641:Phenotype; D034622:RNA Interference; D012330:RNA, Double-Stranded / Q000235:genetics; D018510:RNA, Helminth / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics*; D016160:Retinoblastoma Protein / Q000235:genetics*; D017381:Spliceosomes / Q000235:genetics; D014844:Vulva / Q000254:growth & development; D016335:Zinc Fingers / Q000235:genetics
D029742:Caenorhabditis elegans Proteins; D012330:RNA, Double-Stranded; D018510:RNA, Helminth; D012097:Repressor Proteins; D016160:Retinoblastoma Protein; C116485:lin-35 protein, C elegans