The Role of the Human Papillomavirus Type 16 Minor Capsid Protein L2 N Terminus During Infection of Human Keratinocytes
Human papillomaviruses include low-risk and high-risk types, where persistent infection of high-risk types, most commonly HPV16 and HPV18, is associated with the progression into anogenital and oropharyngeal cancers. HPV DNA is found in over 90% of cervical and anal cancers and over 60% of other genital cancers. Cervical cancer caused over 340,000 deaths in 2020. The minor capsid protein L2 is exposed after the initial binding to the cell or extracellular matrix and is involved in multiple roles including viral trafficking towards the nucleus. Current vaccines target the major capsid protein L1 and are effective against the select types they target, but are ineffective against types not covered as well as for those already infected with HPV. Additionally, vaccine distribution is impeded by a lack of economic infrastructure in developing countries, where incident rates are highest. Understanding of how the virus traffics is essential for the development of additional preventatives and antivirals.This dissertation focuses on the 43-DQILQ-47 sequence of HPV16 L2. Substitution of the isoleucine and leucine residues with alanine resulted in noninfectious virus that trafficked normally to the ER, but lacked association with ER proteins BiP and syntaxin 18. Mutant pseudovirions instead were deferred to the lysosome for degradation. Immunoprecipitation of syntaxin 18 and HPV16 was also lost in mutant pseudovirions that contained the substitution of isoleucine and leucine with alanine. To explore the interaction of this sequence with ER trafficking, an antibody targeting the 39-52 region of HPV16 L2 was produced to determine the time of sequence exposure from the capsid. The neutralizing antibody was able to bind to the 39-52 region after initial particle binding and before furin cleavage of the N terminus. The antibody was also able to cross react with HPV5, HPV6, and HPV31. To explore features of the ER utilized by HPV, the impact of a chemical inhibitor of BiP functionality, HA15, was assessed and determined to decrease infectivity of HPV. This data suggests that the 43-DQILQ-47 sequence of HPV16 L2 is exposed prior to entry to assist in the trafficking to the ER, potentially for uncoating of the viral capsid by BiP.
Virology|Cellular biology|Molecular biology
Morante, Anthony Vincent, "The Role of the Human Papillomavirus Type 16 Minor Capsid Protein L2 N Terminus During Infection of Human Keratinocytes" (2023). ETD Collection for Fordham University. AAI30634368.