Structural basis of TFIIIC-dependent RNA polymerase III transcription initiation

Talyzina, Anna; Han, Yanping; Banerjee, Chiranjib; Fishbain, Susan; Reyes, Alexis; Vafabakhsh, Reza; He, Yuan

doi:10.1016/j.molcel.2023.06.015

Cited by 7 publications

(1 citation statement)

References 87 publications

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“…Transcription factor TFIIIC has been extensively studied in organisms ranging from yeast to vertebrates (Dieci et al 2013 ; Talyzina et al 2023 ). Nevertheless, the knowledge about TFIIIC in early diverged eukaryotes is practically nonexistent.…”

Section: Discussionmentioning

confidence: 99%

Characterization of Tau95 led to the identification of a four-subunit TFIIIC complex in trypanosomatid parasites

Mondragón-Rosas,

Florencio-Martínez,

Villa-Delavequia

et al. 2024

Appl Microbiol Biotechnol

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RNA polymerase III (RNAP III) synthetizes small essential non-coding RNA molecules such as tRNAs and 5S rRNA. In yeast and vertebrates, RNAP III needs general transcription factors TFIIIA, TFIIIB, and TFIIIC to initiate transcription. TFIIIC, composed of six subunits, binds to internal promoter elements in RNAP III-dependent genes. Limited information is available about RNAP III transcription in the trypanosomatid protozoa Trypanosoma brucei and Leishmania major, which diverged early from the eukaryotic lineage. Analyses of the first published draft of the trypanosomatid genome sequences failed to recognize orthologs of any of the TFIIIC subunits, suggesting that this transcription factor is absent in these parasites. However, a putative TFIIIC subunit was recently annotated in the databases. Here we characterize this subunit in T. brucei and L. major and demonstrate that it corresponds to Tau95. In silico analyses showed that both proteins possess the typical Tau95 sequences: the DNA binding region and the dimerization domain. As anticipated for a transcription factor, Tau95 localized to the nucleus in insect forms of both parasites. Chromatin immunoprecipitation (ChIP) assays demonstrated that Tau95 binds to tRNA and U2 snRNA genes in T. brucei. Remarkably, by performing tandem affinity purifications we identified orthologs of TFIIIC subunits Tau55, Tau131, and Tau138 in T. brucei and L. major. Thus, contrary to what was assumed, trypanosomatid parasites do possess a TFIIIC complex. Other putative interacting partners of Tau95 were identified in T. brucei and L. major. Key points • A four-subunit TFIIIC complex is present in T. brucei and L. major • TbTau95 associates with tRNA and U2 snRNA genes • Putative interacting partners of Tau95 might include some RNAP II regulators

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Section: Discussionmentioning

confidence: 99%

Characterization of Tau95 led to the identification of a four-subunit TFIIIC complex in trypanosomatid parasites

Mondragón-Rosas,

Florencio-Martínez,

Villa-Delavequia

et al. 2024

Appl Microbiol Biotechnol

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The choreography of chromatin in RNA polymerase III regulation

van Breugel,

Gerber,

van Leeuwen

2024

Biochemical Society Transactions

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Regulation of eukaryotic gene expression involves a dynamic interplay between the core transcriptional machinery, transcription factors, and chromatin organization and modification. While this applies to transcription by all RNA polymerase complexes, RNA polymerase III (RNAPIII) seems to be atypical with respect to its mechanisms of regulation. One distinctive feature of most RNAPIII transcribed genes is that they are devoid of nucleosomes, which relates to the high levels of transcription. Moreover, most of the regulatory sequences are not outside but within the transcribed open chromatin regions. Yet, several lines of evidence suggest that chromatin factors affect RNAPIII dynamics and activity and that gene sequence alone does not explain the observed regulation of RNAPIII. Here we discuss the role of chromatin modification and organization of RNAPIII transcribed genes and how they interact with the core transcriptional RNAPIII machinery and regulatory DNA elements in and around the transcribed genes.

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Minimization and complete loss of general transcription factor proteins in the intracellular parasite Encephalitozoon cuniculi

Belkevich,

Khalil,

Decatur

et al. 2024

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Structural basis of TFIIIC-dependent RNA polymerase III transcription initiation

Cited by 7 publications

References 87 publications

Characterization of Tau95 led to the identification of a four-subunit TFIIIC complex in trypanosomatid parasites

Characterization of Tau95 led to the identification of a four-subunit TFIIIC complex in trypanosomatid parasites

The choreography of chromatin in RNA polymerase III regulation

Minimization and complete loss of general transcription factor proteins in the intracellular parasite Encephalitozoon cuniculi

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