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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.

Ceron J, Rual JF, Chandra A, Dupuy D, Vidal M, van den Heuvel S - BMC Dev. Biol. (2007)

Bottom Line: 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.Our data support novel hypotheses about possibilities for anti-cancer therapies and multilevel regulation of gene expression.

View Article: PubMed Central - HTML - PubMed

Affiliation: Massachusetts General Hospital Cancer Center and Harvard Medical School, Charlestown, MA 02129, USA. jceron@ir.vhebron.net

ABSTRACT

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.

Conclusion: 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.

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Novel roles of specific spliceosome components in the synMuv B pathway. RSR-2, LSM-2, LSM-4 and SM proteins may have functions that reduce gene expression and are independent of pre-mRNA splicing. The phenotypic overlap with lin-35 Rb mutants may indicate functions in transcription repression, chromatin modification, miRNA/RNAi pathway modulation or mRNA metabolism.
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Figure 5: Novel roles of specific spliceosome components in the synMuv B pathway. RSR-2, LSM-2, LSM-4 and SM proteins may have functions that reduce gene expression and are independent of pre-mRNA splicing. The phenotypic overlap with lin-35 Rb mutants may indicate functions in transcription repression, chromatin modification, miRNA/RNAi pathway modulation or mRNA metabolism.

Mentions: Further studies will be needed to examine potential coupling between transcription, splicing and RNAi-related processes. Based on the overlapping loss-of-function phenotypes, we propose a model in which specific splicing components cooperate with lin-35 synMuv B complexes in repression of gene expression, either by promoting mRNA turnover/translation inhibition or by taking part in multi-protein complexes that regulate transcription, chromatin remodeling, and/or miRNA/RNAi mediated post-transcriptional gene silencing (Figure 5).


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.

Ceron J, Rual JF, Chandra A, Dupuy D, Vidal M, van den Heuvel S - BMC Dev. Biol. (2007)

Novel roles of specific spliceosome components in the synMuv B pathway. RSR-2, LSM-2, LSM-4 and SM proteins may have functions that reduce gene expression and are independent of pre-mRNA splicing. The phenotypic overlap with lin-35 Rb mutants may indicate functions in transcription repression, chromatin modification, miRNA/RNAi pathway modulation or mRNA metabolism.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC1863419&req=5

Figure 5: Novel roles of specific spliceosome components in the synMuv B pathway. RSR-2, LSM-2, LSM-4 and SM proteins may have functions that reduce gene expression and are independent of pre-mRNA splicing. The phenotypic overlap with lin-35 Rb mutants may indicate functions in transcription repression, chromatin modification, miRNA/RNAi pathway modulation or mRNA metabolism.
Mentions: Further studies will be needed to examine potential coupling between transcription, splicing and RNAi-related processes. Based on the overlapping loss-of-function phenotypes, we propose a model in which specific splicing components cooperate with lin-35 synMuv B complexes in repression of gene expression, either by promoting mRNA turnover/translation inhibition or by taking part in multi-protein complexes that regulate transcription, chromatin remodeling, and/or miRNA/RNAi mediated post-transcriptional gene silencing (Figure 5).

Bottom Line: 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.Our data support novel hypotheses about possibilities for anti-cancer therapies and multilevel regulation of gene expression.

View Article: PubMed Central - HTML - PubMed

Affiliation: Massachusetts General Hospital Cancer Center and Harvard Medical School, Charlestown, MA 02129, USA. jceron@ir.vhebron.net

ABSTRACT

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.

Conclusion: 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.

Show MeSH
Related in: MedlinePlus