In retrovirus infections, such as human immunodeficiency virus type 1 (HIV-1) infection, control of alternative splicing is crucial and a number of studies showed that virion production is regulated by SR proteins, including ASF/SF2, SC35 and 9G8 [29] while SRp75 acts to upregulate HIV-1 genes expression [30]. The gene discussed is SLU7; the disease is HIV-1 infection.