A genome-wide haploid genetic screen identifies heparan sulfate-associated genes and the macropinocytosis modulator TMED10 as factors supporting vaccinia virus infection.

Vaccinia virus is a promising viral vaccine and gene delivery candidate, and has historically been used as a model to study poxvirus-host cell interactions. We employed a genome-wide insertional mutagenesis approach in human haploid cells to identify host factors crucial for vaccinia virus infection. A library of mutagenized HAP1 cells was exposed to Modified Vaccinia Virus Ankara (MVA). Deep-sequencing analysis of virus-resistant cells identified host factors involved in heparan sulfate synthesis, Golgi organization, and vesicular protein trafficking. We validated EXT1, TM9SF2 and TMED10 (TMP21/p23/p246) as important host factors for vaccinia virus infection. The critical role of EXT1 in heparan sulfate synthesis and vaccinia virus infection was confirmed. TM9SF2 was validated as a player mediating heparan sulfate expression, explaining its contribution to vaccinia virus infection. In addition, TMED10 was found to be crucial for virus-induced plasma membrane blebbing and phosphatidylserine-induced macropinocytosis, presumably by regulating the cell surface expression of the TAM receptor Axl. [ABSTRACT FROM AUTHOR]