Polr3a mutant vs wild-type
Ontology highlight
ABSTRACT:
ORGANISM(S): Danio rerio
PROVIDER: GSE315895 | GEO | 2026/05/16
REPOSITORIES: GEO
Similar Datasets
Project description:RNA polymerase III (Pol III) is an essential enzyme responsible for the synthesis of several small non-coding RNAs, a number of which are involved in mRNA translation. Recessive mutations in POLR3A, encoding the largest subunit of Pol III, cause POLR3-related hypomyelinating leukodystrophy (POLR3-HLD), characterized by deficient central nervous system myelination. Identification of the downstream effectors of pathogenic POLR3A mutations has been so far elusive. Here, we used CRISPR-Cas9 to introduce the POLR3A mutation c.2554A>G (p.M852V) into human cell lines and assessed its impact on Pol III biogenesis, nuclear import, DNA occupancy, transcription, and protein levels. Transcriptomic profiling uncovered a subset of transcripts vulnerable to Pol III hypofunction, including a global reduction in tRNA levels. The brain cytoplasmic BC200 RNA (BCYRN1), involved in translation regulation, was consistently affected in all our cellular models, including patient-derived fibroblasts. Genomic BC200 deletion in an oligodendroglial cell line led to major transcriptomic and proteomic changes, having a larger impact than those of POLR3A mutations. Upon differentiation, mRNA levels of the MBP gene, encoding myelin basic protein, were significantly decreased in POLR3A-mutant cells. Our findings provide the first evidence for impaired Pol III transcription in cellular models of POLR3-HLD and identify several candidate effectors, including BC200 RNA, having a potential role in oligodendrocyte biology and involvement in the disease.
2019-03-20 | GSE118739 | GEO
Project description:POLR3A ChIPseq in MDA-231 and MDA-LM2 cells
2022-11-25 | GSE140957 | GEO
Project description:Background: Hypomyelinating leukodystrophies (HLDs) are rare genetic neurodevelopmental disorders characterized by defective myelin formation. The genetic cause of these disorders has been ascribed to mutations in genes encoding myelin protein components, such as proteolipid protein 1 (PLP1) and myelin basic protein (MBP), or in genes encoding for transcription and translation-related proteins. Particularly, biallelic pathogenic variants in POLR3A, POLR3B, POLR3K, POLR3D, POLR1C lead to the insurgence of RNA Polymerase III (Pol III)-related HLDs (POLR3-HLDs). The molecular mechanisms linking Pol III dysfunction to hypomyelination remain largely elusive, though the main hypothesis is that impaired Pol III activity likely disrupts gene expression and cellular homeostasis processes critical for myelin development and lipid metabolism. Methods: In this study, we analyzed a family trio consisting of unaffected carrier parents and a proband affected by POLR3A-related HLD, carrying compound heterozygous variants (p.Phe601Tyr and p.Gly1358Arg). We investigated the structural and functional consequences of two POLR3A variants using protein modeling, functional assays and multi-omics profiling in subject-specific primary fibroblasts. Results: Structural analysis revealed alterations in DNA-binding regions and a likely impact on protein stability, whilst functional assays showed an impairment in cellular proliferation. Lipidomic and transcriptomic profiling revealed that p. Gly1358Arg mutation predominantly affects lipidomic metabolism, while p. Phe601Tyr was associated with a widespread transcriptional dysregulation. Both mutations ultimately caused a significant reduction in lipid droplets in the proband’s cells. Conclusions: These results demonstrate mutation-specific pathogenetic mechanisms in POLR3A-HLD and underline the utility of integrative multi-omics approaches in elucidating the molecular basis of rare neurodevelopmental disorders.
2026-02-20 | GSE318114 | GEO
Project description:Progesterone receptor and the RNA polymerase III subunit POLR3A co-occupy tRNAs in breast cancer cells
| PRJNA1196447 | ENA
Project description:Progesterone receptors (PR) can regulate transcription by RNA Polymerase III (Pol III), which transcribes small non-coding RNAs, including all transfer RNAs (tRNAs). Previous work demonstrated that PR associates with the Pol III complex at tRNA genes and that progestins downregulate tRNA transcripts in breast tumor models. To further elucidate the mechanism of PR-mediated regulation of Pol III, we performed ChIP-seq for PR, the Pol III subunit POLR3A, the TFIIIB component Brf1, and the Pol III repressor Maf1 in breast cancer cells with or without progestin treatment. Upon progestin exposure, PR localized to approximately half of POLR3A-occupied tRNA genes, with Maf1 co-recruited to many of these PR-POLR3A sites. While progestin treatment did not significantly alter the number of tRNA genes occupied by Pol III or Brf1, Brf1 occupancy was stabilized, as indicated by increased peak amplitudes. Analysis of nascent tRNA transcription revealed a specific progestin-induced downregulation of approximately one-third of highly expressed tRNA genes. This repression was significantly reduced by Maf1 knockdown, indicating that Maf1 is necessary for PR-mediated tRNA downregulation. Additionally, PR co-immunoprecipitated with Maf1 along with Brf1 and POLR3A. Overall, these findings demonstrate a ligand-dependent PR-mediated repression of tRNA transcription through Maf1.
2025-09-29 | GSE283978 | GEO
Project description:The PR domain containing 1a, with ZNF domain factor, gene prdm1a plays an integral role in the development of a number of different cell types during vertebrate embryogenesis, including neural crest cells, Rohon-Beard (RB) sensory neurons and the cranial neural crest-derived craniofacial skeletal elements. To better understand how Prdm1a regulates the development of various cell types in zebrafish, we performed a microarray analysis comparing wild type and prdm1a mutant embryos and identified a number of genes with altered expression in the absence of prdm1a. Rescue analysis determined that two of these, sox10 and islet1, lie downstream of Prdm1a in the development of neural crest cells and Rohon-Beard neurons, respectively. In addition, we identified a number of other novel downstream targets of Prdm1a that may be important for the development of diverse tissues during zebrafish embryogenesis.
2011-03-29 | GSE28199 | GEO
Project description:Leukodystrophy-associated POLR3A mutations down-regulate the RNA polymerase III transcript and important regulatory RNA BC200
| PRJNA486660 | ENA
Project description:Pathogenic variants in subunits of RNA polymerase (Pol) III cause a spectrum of neurodegenerative diseases including 4H leukodystrophy. We developed a postnatal whole-body mouse model expressing pathogenic mutations in Polr3a to examine the molecular mechanisms by which reduced Pol III activity results primarily in central nervous system phenotypes. Polr3a mutant mice exhibit behavioral deficits, exocrine pancreatic atrophy and cerebral pathology. Transcriptome and immunohistochemistry analyses of cerebra show a reduction in most Pol III transcripts, induction of innate immune and integrated stress responses and cell type-specific gene expression changes reflecting neuron and oligodendrocyte loss and microglial activation. A global decrease in mature tRNA levels and an altered tRNA profile preceded cerebral neurodegeneration suggesting a causal role in disease initiation. In cerebella, heart and kidney, Pol III transcripts other than tRNAs were generally unaffected. The results suggest tissue-specific thresholds of sensitivity to defects in Pol III transcription.
2024-01-10 | GSE246160 | GEO
Project description:Pathogenic variants in subunits of RNA polymerase (Pol) III cause a spectrum of neurodegenerative diseases including 4H leukodystrophy. We developed a postnatal whole-body mouse model expressing pathogenic mutations in Polr3a to examine the molecular mechanisms by which reduced Pol III activity results primarily in central nervous system phenotypes. Polr3a mutant mice exhibit behavioral deficits, exocrine pancreatic atrophy and cerebral pathology. Transcriptome and immunohistochemistry analyses of cerebra show a reduction in most Pol III transcripts, induction of innate immune and integrated stress responses and cell type-specific gene expression changes reflecting neuron and oligodendrocyte loss and microglial activation. A global decrease in mature tRNA levels and an altered tRNA profile preceded cerebral neurodegeneration suggesting a causal role in disease initiation. In cerebella, heart and kidney, Pol III transcripts other than tRNAs were generally unaffected. The results suggest tissue-specific thresholds of sensitivity to defects in Pol III transcription.
2024-01-10 | GSE246161 | GEO