{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,15]],"date-time":"2026-04-15T20:58:29Z","timestamp":1776286709090,"version":"3.50.1"},"reference-count":45,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2019,1,9]],"date-time":"2019-01-09T00:00:00Z","timestamp":1546992000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"the Project of Natural Science Foundation of China","award":["31470258"],"award-info":[{"award-number":["31470258"]}]},{"name":"he State Key Laboratory of Pathogen and Biosecurity (Academy of Military Medical Science","award":["SKLPBS1449"],"award-info":[{"award-number":["SKLPBS1449"]}]},{"name":"Shandong &quot;Double Tops&quot; Program","award":["515-564013 and SYL2017YSTD12"],"award-info":[{"award-number":["515-564013 and SYL2017YSTD12"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Viruses"],"abstract":"<jats:p>The polymerase acidic (PA) protein is the third subunit of the influenza A virus polymerase. In recent years, studies have shown that PA plays an important role in overcoming the host species barrier and host adaptation of the avian influenza virus (AIV). The objective of this study was to elucidate the role of the PA subunit on the replication and airborne transmission of the H9N2 subtype AIV. By reverse genetics, a reassortant rSD01-PA was derived from the H9N2 subtype AIV A\/Chicken\/Shandong\/01\/2008 (SD01) by introducing the PA gene from the pandemic influenza A H1N1 virus A\/swine\/Shandong\/07\/2011 (SD07). Specific pathogen-free (SPF) chickens and guinea pigs were selected as the animal models for replication and aerosol transmission studies. Results show that rSD01-PA lost the ability of airborne transmission among SPF chickens because of the single substitution of the PA gene. However, rSD01-PA could infect guinea pigs through direct contact, while the parental strain SD01 could not, even though the infection of rSD01-PA could not be achieved through aerosol. In summary, our results indicate that the protein encoded by the PA gene plays a key role in replication and airborne transmission of the H9N2 subtype AIV.<\/jats:p>","DOI":"10.3390\/v11010040","type":"journal-article","created":{"date-parts":[[2019,1,10]],"date-time":"2019-01-10T03:22:31Z","timestamp":1547090551000},"page":"40","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":9,"title":["The PA Subunit of the Influenza Virus Polymerase Complex Affects Replication and Airborne Transmission of the H9N2 Subtype Avian Influenza Virus"],"prefix":"10.3390","volume":"11","author":[{"given":"Mengchan","family":"Hao","sequence":"first","affiliation":[{"name":"College of Veterinary Medicine, Shandong Agricultural University, 61 Daizong Street, Taian 271018, China"},{"name":"Collaborative Innovation Center for the Origin and Control of Emerging Infectious Diseases, Taishan Medical University, Taian 270016, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Shaojie","family":"Han","sequence":"additional","affiliation":[{"name":"College of Veterinary Medicine, Shandong Agricultural University, 61 Daizong Street, Taian 271018, China"},{"name":"Collaborative Innovation Center for the Origin and Control of Emerging Infectious Diseases, Taishan Medical University, Taian 270016, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Dan","family":"Meng","sequence":"additional","affiliation":[{"name":"College of Veterinary Medicine, Shandong Agricultural University, 61 Daizong Street, Taian 271018, China"},{"name":"Collaborative Innovation Center for the Origin and Control of Emerging Infectious Diseases, Taishan Medical University, Taian 270016, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Rong","family":"Li","sequence":"additional","affiliation":[{"name":"College of Veterinary Medicine, Shandong Agricultural University, 61 Daizong Street, Taian 271018, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jing","family":"Lin","sequence":"additional","affiliation":[{"name":"College of Veterinary Medicine, Shandong Agricultural University, 61 Daizong Street, Taian 271018, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Meng","family":"Wang","sequence":"additional","affiliation":[{"name":"College of Veterinary Medicine, Shandong Agricultural University, 61 Daizong Street, Taian 271018, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Tong","family":"Zhou","sequence":"additional","affiliation":[{"name":"College of Veterinary Medicine, Shandong Agricultural University, 61 Daizong Street, Taian 271018, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Tongjie","family":"Chai","sequence":"additional","affiliation":[{"name":"College of Veterinary Medicine, Shandong Agricultural University, 61 Daizong Street, Taian 271018, China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2019,1,9]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"D49","DOI":"10.1016\/j.vaccine.2008.07.039","article-title":"The biology of influenza viruses","volume":"26","author":"Bouvier","year":"2008","journal-title":"Vaccine"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"325","DOI":"10.1016\/j.virusres.2010.10.032","article-title":"The N terminus of PA polymerase of swine-origin influenza virus H1N1 determines its compatibility with PB2 and PB1 subunits through a strain-specific amino acid serine 186","volume":"155","author":"Wanitchang","year":"2011","journal-title":"Virus Res."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"31","DOI":"10.1016\/j.jcv.2016.05.017","article-title":"Serologic evidence of exposure to influenza D virus among persons with occupational contact with cattle","volume":"81","author":"White","year":"2016","journal-title":"J. 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