Similar Datasets
Project description:The SSU Processome (sometimes referred to as 90S) is an early stable intermediate in the small ribosomal subunit biogenesis pathway of eukaryotes. Progression of the SSU Processome to a pre-40S particle requires a large-scale compaction of the RNA and release of many biogenesis factors. The U3 snoRNA is a primary component of the SSU Processome and hybridizes to the rRNA at multiple locations to organize the structure of the SSU Processome. Thus, release of U3 is prerequisite for the transition to pre-40S. Our lab proposed that the RNA helicase Dhr1 plays a crucial role in the transition by unwinding U3 and that this activity is controlled by the SSU Processome protein Utp14. How Utp14 times the activation of Dhr1 is an open question. Despite being highly conserved, Utp14 contains no recognizable domains, and how Utp14 interacts with the SSU Processome is not well characterized. Here, we used UV crosslinking and analysis of cDNA (CRAC) and yeast two-hybrid interaction to characterize how Utp14 interacts with the pre-ribosome. Moreover, proteomic analysis of SSU particles lacking Utp14 revealed that the presence of Utp14 is needed for efficient recruitment of the RNA exosome. Our analysis positions Utp14 to be uniquely poised to communicate the status of assembly of the SSU Processome to Dhr1 and possibly to the exosome as well.
2018-06-21 | GSE115748 | GEO
Project description:4C procedure was used for analysis of genomic contacts of rDNA units in HEK 293T cells. The primers for 4C were selected inside IGS. Our data indicate that mostly rDNA units exhibit close proximity with pericentromeric regions in different chromosomes. We also detected the contacts within a rDNA unit and between rDNA units. Examination of rDNA genome-wide contacts in HEK 293T cells using 4C approach.
2014-10-04 | E-GEOD-49193 | biostudies-arrayexpress
Project description:Ribosome small subunit (SSU) is assembled by the SSU processome which contains approximately 70 non-ribosomal protein factors. The biochemical mechanism for the SSU processome in 18S rRNA processing and maturation has been extensively studied, however, how the SSU processome components enter to the nucleolus has not been systematically investigated. Here we checked the nucleolar localization of 50 human SSU processome components and find that UTP3 and other 24 proteins enter to the nucleolus autonomously. For the remaining 25 proteins we find that UTP3/SAS10 assists the nucleolar localization of five proteins, namely MPP10, UTP25, EMG1 and two UTP-B components UTP12 and UTP13, and this ferry function of UTP3 is conserved in zebrafish. We also find that knockdown of human UTP3 impairs the cleavage at A0-site while loss-of-function of either utp3/sas10 or utp13/tbl3 in zebrafish causes an accumulation of the processed products containing the 5′ETS, supporting the crucial role of UTP3 in mediating the 5′ETS processing and degradation. Moreover, UTP3 directly interacts with and delivers EXOSC10 into the nucleolus, suggesting that UTP3 may play a direct role in recruiting the nuclear exosome to the SSU processome for degradation of the processed 5′ETS. These findings lay the ground for studying the mechanism of cytoplasm-to-nucleolus trafficking of the SSU processome components and the multifaceted roles of UTP3 during pre-rRNA processing.
2024-09-18 | GSE262698 | GEO
Project description:Transcription of the several hundred of mouse and human Ribosomal RNA (rRNA) genes accounts for the majority of RNA synthesis in the cell nucleus and is the determinant of cytoplasmic ribosome abundance, a key factor in regulating gene expression. The rRNA genes, referred to globally as the rDNA, are clustered as direct repeats at the Nucleolar Organiser Regions, NORs, of several chromosomes, and in many cells the active repeats are transcribed at near saturation levels. The rDNA is also a hotspot of recombination and chromosome breakage, and hence understanding its control has broad importance. Despite the need for a high level of rDNA transcription, typically only a fraction of the rDNA is transcriptionally active, and some NORs are permanently silenced by CpG methylation. Various chromatin-remodelling complexes have been implicated in counteracting silencing to maintain rDNA activity. However, the chromatin structure of the active rDNA fraction is still far from clear. Here we have combined a high-resolution ChIP-Seq protocol with conditional inactivation of key basal factors to better understand what determines active rDNA chromatin. The data resolve questions concerning the interdependence of the basal transcription factors, show that preinitiation complex formation is driven by the architectural factor UBF (UBTF) independently of transcription, and exclude a significant role for termination by a torpedomechanism. They further reveal the existence of an asymmetric Boundary Complex formed by CTCF, Cohesin and three phased nucleosomes lying adjacent to the rDNA Enhancer and an arrested RNA Polymerase I complex. We find that this complex is the only site of active histone modification in the whole 45kbp rDNA repeat. Strikingly, the Enhancer Boundary Complex not only delimits each functional rRNA gene, but also is stably maintained after gene inactivation and the re-establishment of surrounding repressive chromatin. Our data define the poised state of rDNA chromatin and place the Enhancer Boundary Complex as the likely entry point for the chromatin remodelling complexes.
2017-07-08 | E-MTAB-5839 | biostudies-arrayexpress
Project description:Data-dependent LC-MS/MS was used to generate a protein inventory of an affinity-purified assembly intermediate of the small subunit (SSU) of the Trypanosoma brucei mitochondrial ribosome. The identified proteins (mitoribosomal proteins and putative maturation factors) were then used to assist in solving the structure of the SSU assemblosome by cryo-electron microscopy.
2019-09-13 | PXD011988 | Pride
Project description:Ribosome is the most abundant RNA-protein complex in a cell and many copies of the ribosomal RNA gene (rDNA) have to be maintained. However, arrays of tandemly repeated rDNA genes can lose the copies by intra-repeat recombination. Loss of the rDNA copies of Saccharomyces cerevisiae is counteracted by gene amplification whereby the number of rDNA repeats stabilizes around 150 copies, suggesting the presence of a monitoring mechanism that counts and adjusts the number. Here, we report that in response to rDNA copy loss, the upstream activating factor (UAF) for RNA polymerase I which transcribes the rDNA is released and directly bind to a RNA polymerase II transcribed gene, SIR2 to repress, whose gene products silence rDNA recombination. We show that the amount of UAF determines rDNA copies number that is stably maintained. UAF ensures rDNA production not only by rDNA transcription activation but also by its copy number maintenance.
2019-01-03 | GSE116661 | GEO