Project description:Elucidation of the biological role of H1 and HP1 in mammals has been difficult owing to the existence of a least 11 distinct H1 and three HP1 subtypes in mice. Therefore we decided to study the function of HP1 (HPL-1 and HPL-2) and H1 (HIS-24) related proteins in C. elegans, since hpls and his-24 deficient nematodes are viable. Global transcriptional analysis of the mutant animals revealed that expression of only a small number of genes was affected and HPLs, and HIS-24 appear to influence the expression of genes through either activation or repression. Interestingly, knockout of HPL-2 and HIS-24 caused chromatin structure changes in the germline without altering core histone modifications. Furthermore, the mutant animals showed abnormal development of the male tail and the ectopic expression of C. elegans HOM-C genes (egl-5 and mab-5) involved in the developmental patterning of the mating structures. Surprisingly, H3K27me3 chromatin mark presented at the C. elegans HOM-C gene promoters was recognized by HPL-2 and methylated form of HIS-24. We propose that methylated HIS-24 and HPL-2 bind independently to PcG target loci that have been trimethylated at H3K27 by C. elegans MES-2 [E(Z)] to transcriptionally repress the Hox genes. Our results establish interplay of the H3K27me3 binding proteins, HP1/HPLs and H1/HIS-24 in the regulation of positional identity in the C. elegans males. The experiment was performed using biological independent replicates of pooled worms. For all KO mutants we used duplicates.
Project description:Elucidation of the biological role of H1 and HP1 in mammals has been difficult owing to the existence of a least 11 distinct H1 and three HP1 subtypes in mice. Therefore we decided to study the function of HP1 (HPL-1 and HPL-2) and H1 (HIS-24) related proteins in C. elegans, since hpls and his-24 deficient nematodes are viable. Global transcriptional analysis of the mutant animals revealed that expression of only a small number of genes was affected and HPLs, and HIS-24 appear to influence the expression of genes through either activation or repression. Interestingly, knockout of HPL-2 and HIS-24 caused chromatin structure changes in the germline without altering core histone modifications. Furthermore, the mutant animals showed abnormal development of the male tail and the ectopic expression of C. elegans HOM-C genes (egl-5 and mab-5) involved in the developmental patterning of the mating structures. Surprisingly, H3K27me3 chromatin mark presented at the C. elegans HOM-C gene promoters was recognized by HPL-2 and methylated form of HIS-24. We propose that methylated HIS-24 and HPL-2 bind independently to PcG target loci that have been trimethylated at H3K27 by C. elegans MES-2 [E(Z)] to transcriptionally repress the Hox genes. Our results establish interplay of the H3K27me3 binding proteins, HP1/HPLs and H1/HIS-24 in the regulation of positional identity in the C. elegans males.
Project description:Linker histone H1 and heterochromatin protein 1 (HP1) are essential components ofheterochromatin which contribute to the transcriptional repression of genes. It has been shown that the methylation mark on the histone H1 serves as a specific recognition code for the chromodomain of HP1, however, the functional role of the HP1/H1 complex remains elusive. Using C. elegans, we elucidate the function of the linker histone variant HIS-24 and heterochromatin proteins HPL/HP1 in the cooperative transcriptional regulation of immunerelevant and stress resistance genes. We also show that HIS-24 and HPL act redundantly in vulval cell fate specification and gonad development. Finally, we provide the first evidence that HPL-1 interacts with HIS-24 at mono-methylated lysine 14 and associates in vivo with promoters of infection-inducible genes: the caenacin (cnc)- and the thaumatin (thn)- gene clusters. Our results highlight a functional link between epigenetic regulation by HP1/H1 the innate immune system and stress response.
Project description:Linker histone H1 and heterochromatin protein 1 (HP1) are essential components ofheterochromatin which contribute to the transcriptional repression of genes. It has been shown that the methylation mark on the histone H1 serves as a specific recognition code for the chromodomain of HP1, however, the functional role of the HP1/H1 complex remains elusive. Using C. elegans, we elucidate the function of the linker histone variant HIS-24 and heterochromatin proteins HPL/HP1 in the cooperative transcriptional regulation of immunerelevant and stress resistance genes. We also show that HIS-24 and HPL act redundantly in vulval cell fate specification and gonad development. Finally, we provide the first evidence that HPL-1 interacts with HIS-24 at mono-methylated lysine 14 and associates in vivo with promoters of infection-inducible genes: the caenacin (cnc)- and the thaumatin (thn)- gene clusters. Our results highlight a functional link between epigenetic regulation by HP1/H1 the innate immune system and stress response. The experiment was performed using biological independent replicates of pooled worms. For the KO mutants we used duplicates and for WT condition quadruplicates.
Project description:To identify methylated small RNAs in C. elegans, we deep sequenced both β-eliminated and untreated small RNAs isolated from wild type C. elegans.