We employed a high-throughput, systematic analysis of 741 dox-repressible essential yeast strains to identify 24 novel, essential host factors that alter BMV RNA replication. Our previous systematic analysis of ,4,500 non-essential yeast deletion strains identified 99 genes that inhibited or enhanced BMV RNA replication [9] . Collectively, we have analyzed ,93% of all yeast genes (,5,800), and the 123 host genes identified to date that affect BMV RNA replication represent 2.3% of the yeast genome. As observed with tomato bushy stunt virus (TBSV) [38] , another positive strand RNA virus, BMV replication is affected, directly or indirectly, by essential genes at a higher frequency (3.2%) than non-essential genes (2.2%).