RESUMO
The transmission of chromatin states from parent cells to daughter cells preserves cell-specific transcriptional states and thus cell identity through cell division. The mechanism that underpins this process is not fully understood. The role that chromatin states serve in transmitting gene expression information across generations via sperm and oocytes is even less understood. Here, we utilized a model in which Caenorhabditis elegans sperm and oocyte alleles were inherited in different states of the repressive mark H3K27me3. This resulted in the alleles achieving different transcriptional states within the nuclei of offspring. Using this model, we showed that sperm alleles inherited without H3K27me3 were sensitive to up-regulation in offspring somatic and germline tissues, and tissue context determined which genes were up-regulated. We found that the subset of sperm alleles that were up-regulated in offspring germlines retained the H3K27me3(-) state and were transmitted to grandoffspring as H3K27me3(-) and up-regulated epialleles, demonstrating that H3K27me3 can serve as a transgenerational epigenetic carrier in C. elegans.
Assuntos
Alelos , Caenorhabditis elegans , Epigênese Genética , Histonas , Espermatozoides , Animais , Caenorhabditis elegans/genética , Cromatina/metabolismo , Histonas/genética , Masculino , Oócitos/metabolismo , Sêmen/metabolismo , Espermatozoides/metabolismoRESUMO
Transcriptomic approaches have provided a growing set of powerful tools with which to study genome-wide patterns of gene expression. Rapidly evolving technologies enable analysis of transcript abundance data from particular tissues and even single cells. This Primer discusses methods that can be used to collect and profile RNAs from specific tissues or cells, process and analyze high-throughput RNA-sequencing data, and define sets of genes that accurately represent a category, such as tissue-enriched or tissue-specific gene expression.
Assuntos
Biologia Computacional , Perfilação da Expressão Gênica/tendências , RNA/genética , Transcriptoma/genética , Animais , Regulação da Expressão Gênica no Desenvolvimento/genética , Genoma/genética , Sequenciamento de Nucleotídeos em Larga Escala/tendências , Especificidade de Órgãos/genéticaRESUMO
Paternal epigenetic inheritance is gaining attention for its growing medical relevance. However, the form in which paternal epigenetic information is transmitted to offspring and how it influences offspring development remain poorly understood. Here we show that in C. elegans, sperm-inherited chromatin states transmitted to the primordial germ cells in offspring influence germline transcription and development. We show that sperm chromosomes inherited lacking the repressive histone modification H3K27me3 are maintained in that state by H3K36me3 antagonism. Inheritance of H3K27me3-lacking sperm chromosomes results in derepression in the germline of somatic genes, especially neuronal genes, predominantly from sperm-inherited alleles. This results in germ cells primed for losing their germ cell identity and adopting a neuronal fate. These data demonstrate that histone modifications are one mechanism through which epigenetic information from a father can shape offspring gene expression and development.
Assuntos
Caenorhabditis elegans/genética , Epigênese Genética , Regulação da Expressão Gênica no Desenvolvimento , Histonas/genética , Herança Paterna , Animais , Caenorhabditis elegans/crescimento & desenvolvimento , Caenorhabditis elegans/metabolismo , Diferenciação Celular , Cromatina/química , Cromatina/metabolismo , Embrião não Mamífero , Histonas/metabolismo , Larva/genética , Larva/crescimento & desenvolvimento , Larva/metabolismo , Masculino , Neurônios/citologia , Neurônios/metabolismo , Espermatozoides/citologia , Espermatozoides/metabolismo , Transcrição GênicaRESUMO
Exposure of mother worms to mild osmotic stress induces gene expression changes in offspring that protect them from strong osmotic stress. Inheritance of protection is now shown to depend on altered insulin-like signalling in the maternal germline, which confers protection through increased expression of zygotic gpdh-2, a rate-limiting enzyme in glycerol biosynthesis.
Assuntos
Caenorhabditis elegans/genética , Caenorhabditis elegans/fisiologia , Citoproteção/genética , Padrões de Herança/genética , Pressão Osmótica , Estresse Fisiológico , Animais , Caenorhabditis elegans/efeitos dos fármacos , Citoproteção/efeitos dos fármacos , Epigênese Genética/efeitos dos fármacos , Padrões de Herança/efeitos dos fármacos , Larva/efeitos dos fármacos , Larva/fisiologia , Modelos Biológicos , Pressão Osmótica/efeitos dos fármacos , Cloreto de Sódio/farmacologia , Estresse Fisiológico/efeitos dos fármacosRESUMO
Before the first zygotic division, the nuclear envelopes of the maternal and paternal pronuclei disassemble, allowing both sets of chromosomes to be incorporated into a single nucleus in daughter cells after mitosis. We found that in Caenorhabditis elegans, partial inactivation of the polo-like kinase PLK-1 causes the formation of two nuclei, containing either the maternal or paternal chromosomes, in each daughter cell. These two nuclei gave rise to paired nuclei in all subsequent cell divisions. The paired-nuclei phenotype was caused by a defect in forming a gap in the nuclear envelopes at the interface between the two pronuclei during the first mitotic division. This was accompanied by defects in chromosome congression and alignment of the maternal and paternal metaphase plates relative to each other. Perturbing chromosome congression by other means also resulted in failure to disassemble the nuclear envelope between the two pronuclei. Our data further show that PLK-1 is needed for nuclear envelope breakdown during early embryogenesis. We propose that during the first zygotic division, PLK-1-dependent chromosome congression and metaphase plate alignment are necessary for the disassembly of the nuclear envelope between the two pronuclei, ultimately allowing intermingling of the maternal and paternal chromosomes.
