Metabolites and metabolic pathways have been reported as key factors related to the regulation of epigenetics as cofactors and substrates. The germ cell lineage involves dynamic epigenetic changes during its formation and differentiation that are completely different from those of the somatic cell lineage. Our study establishes that Spt4, together with Spt5m, is essential for expression of the germline genome and necessary for developmental genome rearrangements. Moreover, we observed that the presence of a germline-specific Spt4-Spt5m complex is necessary for transfer of the scnRNA-binding PIWI protein between the germline and somatic nucleus. Silencing of the SPT4 genes resulted in the absence of double-stranded ncRNAs and reduced levels of scnRNAs – 25 nt-long sRNAs produced from these double-stranded precursors in the germline nucleus. SPT4 genes are not essential in vegetative growth, but they are indispensable for sexual reproduction, even though genes from both expression families show functional redundancy. tetraurelia by two genes expressed constitutively and two genes expressed during meiosis. We focused our study on Spt4, a small zinc-finger protein encoded in P.
#Hypertranscribe free series
This phenomenon starts a series of events mediated by different classes of non-coding RNAs that control developmentally programmed DNA elimination. In this organism harboring both germline and somatic nuclei, massive transcription of the entire germline genome takes place during meiosis. To investigate the role of the Spt4-Spt5 complex in non-coding transcription during development, we used the unicellular model Paramecium tetraurelia. The Spt4-Spt5 complex is conserved and essential RNA polymerase elongation factor. Our findings reveal an intriguing link between rRNA synthesis, nucleolar maturation, and gene repression during early development. In embryos, nucleolar disruption prevents proper nucleolar maturation and Dux silencing and leads to two- to four-cell arrest.
#Hypertranscribe free Activator
We reveal that nucleolar disruption via blocking RNA polymerase I activity or preventing nucleolar phase separation enhances conversion to a 2C-like state in embryonic stem cells (ESCs) by detachment of the MERVL activator Dux from the nucleolar surface. 2C-like cells and two-cell embryos show similar immature nucleoli with altered structure and reduced rRNA output. Here, we report that robust ribosomal RNA (rRNA) synthesis and nucleolar maturation are essential for exit from the 2C state. Moreover, this MERVL-driven transcriptional program must be rapidly shut off to allow two-cell exit and developmental progression.
The mechanisms and requirement for MERVL and two-cell (2C) gene up-regulation are poorly understood. Upon fertilization, the mammalian embryo must switch from dependence on maternal transcripts to transcribing its own genome, and in mice this involves the transient up-regulation of MERVL transposons and MERVL-driven genes at the two-cell stage.
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