Genome structure and gene expression of SARS-CoV-2 virus

Zaraza virusom SARS-CoV-2, nazvana COVID-19, obilježila je posljednje 3 godine. U tom razdoblju novootkriveni korona virus intenzivno se istražuje kako bi se bolje razumjela njegova svojstva i način prenošenja, te pronašle pogodne mete za razvoj učinkovitih antivrusnih lijekova. Genom virusa SARS-CoV-2 koji je kodirajući (+) lanac jednolančane pozitivne ribonukleinske kiseline, a zajedno s proteinima membrane, nukleokapside, omotnice i glikoproteinom šiljka čini virusnu česticu SARS-CoV-2. Genetički materijal u stanicu domaćina ulazi reakcijom glikoproteina šiljka i receptora domaćina angiotensin 1 konvertirajućeg enzima. Nakon ulaska u stanicu, dolazi do translacije RNA virusa prilikom čega nastaje 16 nestruktrurnih proteina koji sudjeluju u ostatku životnog ciklusa. Također, formiraju replikacijsko-transkripcijski kompleks koji provodi kontinuiranu i diskontinuiranu transkripciju. Diskontinuirana transkripcija je jedinstveno obilježje korona virusa te se odvija mehanizmom zamjene kalupa, a rezultira subgenomskom RNA čijom ekspresijom nastaju strukturni proteini. Unatoč lektorirajućoj aktivnost nestrukturnog proteina 14 koji sudjeluje u transkripciji RNA, SARS-CoV-2 karakterizira velik broj mutacija, a time i novih sojeva, među kojima su oni koji izazivaju zabrinutost: alfa, beta, gama, delta i najnoviji, omikron.SARS-CoV-2 infection, or COVID-19, has strongly affected the last three years. During this period, the newly discovered coronavirus wasintensively researched in order to better understand its properties and mode of transmission, and to find suitable targets for the development of effective antiviral drugs. SARS-CoV-2 virus has a single-stranded, positive-sense(+)RNA genome which together with membrane, nucleocapsid, envelope, and spike protein, makes viral particles. Interaction of host-cell receptor angiotensin 1 converting enzyme 2 (ACE2) with spike protein leads to the release of virus genetic material into the host cell. After entering the cell, RNA translation occurs, giving rise to 16 nonstructural proteins with an essential role in the rest of the virus life cycle. Also, they form a replication-transcription complex that carries out continuous and discontinuous transcription. Discontinuous transcription is a unique feature of coronaviruses that functions by template switching. It yields a set of subgenomic RNAs used to express structural proteins. Despite the proofreading activity of nonstructural protein 14, SARS-CoV-2 is characterized by many mutations, resulting with new variants, some of which are variants of concern (VOC). These variants are alpha, beta, gamma, delta, and most recent, omicron