Upstream Stimulatory Factors Regulate HIV-1 Latency and Are Required for Robust T Cell Activation
HIV-1 provirus expression is controlled by signaling pathways that are responsive to T cell receptor engagement, including those involving Ras and downstream protein kinases. The induction of transcription from the HIV-1 LTR in response to Ras signaling requires binding of the Ras-responsive element...
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| Format: | Article |
| Language: | English |
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MDPI AG
2023-06-01
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| Series: | Viruses |
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| Online Access: | https://www.mdpi.com/1999-4915/15/7/1470 |
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| author | Riley M. Horvath Ivan Sadowski |
| author_facet | Riley M. Horvath Ivan Sadowski |
| author_sort | Riley M. Horvath |
| collection | DOAJ |
| description | HIV-1 provirus expression is controlled by signaling pathways that are responsive to T cell receptor engagement, including those involving Ras and downstream protein kinases. The induction of transcription from the HIV-1 LTR in response to Ras signaling requires binding of the Ras-responsive element binding factor (RBF-2) to conserved <i>cis</i> elements flanking the enhancer region, designated RBE3 and RBE1. RBF-2 is composed minimally of the USF1, USF2, and TFII-I transcription factors. We recently determined that TFII-I regulates transcriptional elongation from the LTR through recruitment of the co-activator TRIM24. However, the function of USF1 and USF2 for this effect are uncharacterized. Here, we find that genetic deletion of <i>USF2</i> but not <i>USF1</i> in T cells inhibits HIV-1 expression. The loss of USF2 caused a reduction in expression of the USF1 protein, an effect that was not associated with decreased <i>USF1</i> mRNA abundance. USF1 and USF2 were previously shown to exist predominately as heterodimers and to cooperatively regulate target genes. To examine cooperativity between these factors, we performed RNA-seq analysis of T cell lines bearing knockouts of the genes encoding these factors. In untreated cells, we found limited evidence of coordinated global gene regulation between USF1 and USF2. In contrast, we observed a high degree of genome-wide cooperative regulation of RNA expression between these factors in cells stimulated with the combination of PMA and ionomycin. In particular, we found that the deletion of <i>USF1</i> or <i>USF2</i> restricted T cell activation response. These observations indicate that USF2, but not USF1, is crucial for HIV-1 expression, while the combined function of these factors is required for a robust T cell inflammatory response. |
| first_indexed | 2024-03-11T00:34:34Z |
| format | Article |
| id | doaj.art-c6753057968341f3afee612b1b2362a7 |
| institution | Directory Open Access Journal |
| issn | 1999-4915 |
| language | English |
| last_indexed | 2024-03-11T00:34:34Z |
| publishDate | 2023-06-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Viruses |
| spelling | doaj.art-c6753057968341f3afee612b1b2362a72023-11-18T21:44:09ZengMDPI AGViruses1999-49152023-06-01157147010.3390/v15071470Upstream Stimulatory Factors Regulate HIV-1 Latency and Are Required for Robust T Cell ActivationRiley M. Horvath0Ivan Sadowski1Molecular Epigenetics Group, Department of Biochemistry and Molecular Biology, LSI, University of British Columbia, Vancouver, BC V6T 1Z3, CanadaMolecular Epigenetics Group, Department of Biochemistry and Molecular Biology, LSI, University of British Columbia, Vancouver, BC V6T 1Z3, CanadaHIV-1 provirus expression is controlled by signaling pathways that are responsive to T cell receptor engagement, including those involving Ras and downstream protein kinases. The induction of transcription from the HIV-1 LTR in response to Ras signaling requires binding of the Ras-responsive element binding factor (RBF-2) to conserved <i>cis</i> elements flanking the enhancer region, designated RBE3 and RBE1. RBF-2 is composed minimally of the USF1, USF2, and TFII-I transcription factors. We recently determined that TFII-I regulates transcriptional elongation from the LTR through recruitment of the co-activator TRIM24. However, the function of USF1 and USF2 for this effect are uncharacterized. Here, we find that genetic deletion of <i>USF2</i> but not <i>USF1</i> in T cells inhibits HIV-1 expression. The loss of USF2 caused a reduction in expression of the USF1 protein, an effect that was not associated with decreased <i>USF1</i> mRNA abundance. USF1 and USF2 were previously shown to exist predominately as heterodimers and to cooperatively regulate target genes. To examine cooperativity between these factors, we performed RNA-seq analysis of T cell lines bearing knockouts of the genes encoding these factors. In untreated cells, we found limited evidence of coordinated global gene regulation between USF1 and USF2. In contrast, we observed a high degree of genome-wide cooperative regulation of RNA expression between these factors in cells stimulated with the combination of PMA and ionomycin. In particular, we found that the deletion of <i>USF1</i> or <i>USF2</i> restricted T cell activation response. These observations indicate that USF2, but not USF1, is crucial for HIV-1 expression, while the combined function of these factors is required for a robust T cell inflammatory response.https://www.mdpi.com/1999-4915/15/7/1470USF1USF2HIV-1latencyLTRRBF-2 |
| spellingShingle | Riley M. Horvath Ivan Sadowski Upstream Stimulatory Factors Regulate HIV-1 Latency and Are Required for Robust T Cell Activation Viruses USF1 USF2 HIV-1 latency LTR RBF-2 |
| title | Upstream Stimulatory Factors Regulate HIV-1 Latency and Are Required for Robust T Cell Activation |
| title_full | Upstream Stimulatory Factors Regulate HIV-1 Latency and Are Required for Robust T Cell Activation |
| title_fullStr | Upstream Stimulatory Factors Regulate HIV-1 Latency and Are Required for Robust T Cell Activation |
| title_full_unstemmed | Upstream Stimulatory Factors Regulate HIV-1 Latency and Are Required for Robust T Cell Activation |
| title_short | Upstream Stimulatory Factors Regulate HIV-1 Latency and Are Required for Robust T Cell Activation |
| title_sort | upstream stimulatory factors regulate hiv 1 latency and are required for robust t cell activation |
| topic | USF1 USF2 HIV-1 latency LTR RBF-2 |
| url | https://www.mdpi.com/1999-4915/15/7/1470 |
| work_keys_str_mv | AT rileymhorvath upstreamstimulatoryfactorsregulatehiv1latencyandarerequiredforrobusttcellactivation AT ivansadowski upstreamstimulatoryfactorsregulatehiv1latencyandarerequiredforrobusttcellactivation |