A genetic screen for suppressors of hyper-repression of the fission yeast PHO regulon by Pol2 CTD mutation T4A implicates inositol 1-pyrophosphates as agonists of precocious lncRNA transcription termination Journal Article
| Authors: | Garg, A.; Shuman, S.; Schwer, B. |
| Article Title: | A genetic screen for suppressors of hyper-repression of the fission yeast PHO regulon by Pol2 CTD mutation T4A implicates inositol 1-pyrophosphates as agonists of precocious lncRNA transcription termination |
| Abstract: | Fission yeast phosphate homeostasis genes are repressed in phosphate-rich medium by transcription of upstream lncRNAs that interferes with activation of the flanking mRNA promoters. lncRNA control of PHO gene expression is influenced by the Thr4 phospho-site in the RNA polymerase II CTD and the 3' processing/termination factors CPF and Rhn1, mutations of which result in hyper-repression of the PHO regulon. Here, we performed a forward genetic screen for mutations that de-repress Pho1 acid phosphatase expression in CTD-T4A cells. Sequencing of 18 independent STF (Suppressor of Threonine Four) isolates revealed, in every case, a mutation in the C-terminal pyrophosphatase domain of Asp1, a bifunctional inositol pyrophosphate (IPP) kinase/pyrophosphatase that interconverts 5-IP7 and 1,5-IP8. Focused characterization of two STF strains identified 51 coding genes coordinately upregulated vis-à-vis the parental T4A strain, including all three PHO regulon genes (pho1, pho84, tgp1). Whereas these STF alleles-asp1-386(Stop) and asp1-493(Stop)-were lethal in a wild-type CTD background, they were viable in combination with mutations in CPF and Rhn1, in which context Pho1 was also de-repressed. Our findings implicate Asp1 pyrophosphatase in constraining 1,5-IP8 or 1-IP7 synthesis by Asp1 kinase, without which 1-IPPs can accumulate to toxic levels that elicit precocious termination by CPF/Rhn1. © The Author(s) 2020. Published by Oxford University Press on behalf of Nucleic Acids Research. |
| Journal Title: | Nucleic Acids Research |
| Volume: | 48 |
| Issue: | 19 |
| ISSN: | 0305-1048 |
| Publisher: | Oxford University Press |
| Date Published: | 2020-11-04 |
| Start Page: | 10739 |
| End Page: | 10752 |
| Language: | English |
| DOI: | 10.1093/nar/gkaa776 |
| PUBMED: | 33010152 |
| PROVIDER: | scopus |
| PMCID: | PMC7641756 |
| DOI/URL: | |
| Notes: | Article -- Export Date: 1 December 2020 -- Source: Scopus |
Altmetric
Citation Impact
BMJ Impact Analytics
Related MSK Work