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Abstract

The human papillomavirus (HPV) belongs to the family of Papillomaviridae with more than 200 members, including HPVs but also papillomaviruses (PV) infecting for example cattle or rodents. Due to the causative association of HPV infection with the development of cervical cancer intensive investigation on HPV has been conducted over the last decades. Therefore, many aspects on the viral structure, infection as well as the transforming properties especially of the high risk HPV types have already been deciphered. In the course of these investigations, the HPV minor capsid protein L2 has been identified as an important player in the establishment of viral infection. Even though, the protein is dispensable for capsid formation, it has been demonstrated to have several functions crucial for e.g. DNA encapsidation, viral entry and the delivery of the viral genome to the host cell nucleus. However, the exact function of L2 during some of these processes is still unknown and under continuous investigation. In this context, many functional domains of the L2 protein have been identified especially in the highly conserved N-terminus of the protein however the function of the remaining parts is still unrevealed. Regarding the importance of the L2 protein for viral infection further investigation on potential functions still represents a promising field of research. The objective of this thesis was the identification of novel cellular interaction partners of L2. To this end, three independent experimental approaches were established, allowing the co-purification of interacting proteins. A) Tandem affinity purification (TAP) a two-step purification method based on the overexpression of HPV16 L2 as fusion protein with the TAP tag. B) Immunoprecipitation (IP) of HPV16 L2 from pseudovirus (PsV) infected cells, mimicking the natural infection pathway of HPV16. C) Peptide pull down of cellular proteins using immobilized HPV16 L2 epitopes which are targets for neutralizing antibodies. For identification of the co-purified interaction candidates the samples derived from the different experimental approaches were analyzed by mass spectrometry (MS).