{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"institution":[{"name":"bioRxiv"}],"indexed":{"date-parts":[[2026,4,13]],"date-time":"2026-04-13T03:33:21Z","timestamp":1776051201159,"version":"3.50.1"},"posted":{"date-parts":[[2023,4,6]]},"group-title":"Microbiology","reference-count":61,"publisher":"openRxiv","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"accepted":{"date-parts":[[2023,4,6]]},"abstract":"<jats:title>ABSTRACT<\/jats:title>\n                <jats:p>Several coronavirus (CoV) encoded proteins are being evaluated as targets for antiviral therapies for COVID-19. Included in this set of proteins is the conserved macrodomain, or Mac1, an ADP-ribosylhydrolase and ADP-ribose binding protein. Utilizing point mutant recombinant viruses, Mac1 was shown to be critical for both murine hepatitis virus (MHV) and severe acute respiratory syndrome (SARS)-CoV virulence. However, as a potential drug target, it is imperative to understand how a complete Mac1 deletion impacts the replication and pathogenesis of different CoVs. To this end, we created recombinant bacterial artificial chromosomes (BACs) containing complete Mac1 deletions (\u0394Mac1) in MHV, MERS-CoV, and SARS-CoV-2. While we were unable to recover infectious virus from MHV or MERS-CoV \u0394Mac1 BACs, SARS-CoV-2 \u0394Mac1 was readily recovered from BAC transfection, indicating a stark difference in the requirement for Mac1 between different CoVs. Furthermore, SARS-CoV-2 \u0394Mac1 replicated at or near wild-type levels in multiple cell lines susceptible to infection. However, in a mouse model of severe infection, \u0394Mac1 was quickly cleared causing minimal pathology without any morbidity. \u0394Mac1 SARS-CoV-2 induced increased levels of interferon (IFN) and interferon-stimulated gene (ISG) expression in cell culture and mice, indicating that Mac1 blocks IFN responses which may contribute to its attenuation. \u0394Mac1 infection also led to a stark reduction in inflammatory monocytes and neutrophils. These results demonstrate that Mac1 only minimally impacts SARS-CoV-2 replication, unlike MHV and MERS-CoV, but is required for SARS-CoV-2 pathogenesis and is a unique antiviral drug target.<\/jats:p>\n                <jats:sec>\n                  <jats:title>SIGNIFICANCE<\/jats:title>\n                  <jats:p>\n                    All CoVs, including SARS-CoV-2, encode for a conserved macrodomain (Mac1) that counters host ADP-ribosylation. Prior studies with SARS-CoV-1 and MHV found that Mac1 blocks IFN production and promotes CoV pathogenesis, which has prompted the development of SARS-CoV-2 Mac1 inhibitors. However, development of these compounds into antivirals requires that we understand how SARS-CoV-2 lacking Mac1 replicates and causes disease\n                    <jats:italic>in vitro<\/jats:italic>\n                    and\n                    <jats:italic>in vivo<\/jats:italic>\n                    . Here we found that SARS-CoV-2 containing a complete Mac1 deletion replicates normally in cell culture but induces an elevated IFN response, has reduced viral loads\n                    <jats:italic>in vivo<\/jats:italic>\n                    , and does not cause significant disease in mice. These results will provide a roadmap for testing Mac1 inhibitors, help identify Mac1 functions, and open additional avenues for coronavirus therapies.\n                  <\/jats:p>\n                <\/jats:sec>","DOI":"10.1101\/2023.04.06.535927","type":"posted-content","created":{"date-parts":[[2023,4,6]],"date-time":"2023-04-06T23:25:16Z","timestamp":1680823516000},"source":"Crossref","is-referenced-by-count":10,"title":["SARS-CoV-2 Mac1 is required for IFN antagonism and efficient virus replication in mice"],"prefix":"10.64898","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-8435-9042","authenticated-orcid":false,"given":"Yousef M.","family":"Alhammad","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Srivatsan","family":"Parthasarathy","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1397-3966","authenticated-orcid":false,"given":"Roshan","family":"Ghimire","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Joseph J.","family":"O\u2019Connor","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Catherine M.","family":"Kerr","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jessica J.","family":"Pfannenstiel","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Debarati","family":"Chanda","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Caden A.","family":"Miller","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Robert L.","family":"Unckless","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Sonia","family":"Zuniga","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0854-0226","authenticated-orcid":false,"given":"Luis","family":"Enjuanes","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5007-8795","authenticated-orcid":false,"given":"Sunil","family":"More","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7608-1922","authenticated-orcid":false,"given":"Rudragouda","family":"Channappanavar","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1560-1573","authenticated-orcid":false,"given":"Anthony R.","family":"Fehr","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"54368","reference":[{"key":"2023041100201275000_2023.04.06.535927v1.1","doi-asserted-by":"publisher","DOI":"10.1007\/978-1-0716-0900-2_1"},{"key":"2023041100201275000_2023.04.06.535927v1.2","doi-asserted-by":"publisher","DOI":"10.1016\/j.cell.2020.04.026"},{"key":"2023041100201275000_2023.04.06.535927v1.3","doi-asserted-by":"publisher","DOI":"10.1016\/S2214-109X(21)00593-3"},{"key":"2023041100201275000_2023.04.06.535927v1.4","doi-asserted-by":"publisher","DOI":"10.1056\/NEJMoa2007764"},{"key":"2023041100201275000_2023.04.06.535927v1.5","doi-asserted-by":"crossref","first-page":"451","DOI":"10.1038\/s41586-021-03312-w","article-title":"SARS-CoV-2 infection is effectively treated and prevented by EIDD-2801","volume":"591","year":"2021","journal-title":"Nature"},{"key":"2023041100201275000_2023.04.06.535927v1.6","doi-asserted-by":"crossref","unstructured":"I. 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