For example, the lipid status of cells regulates the replication and infectivity of hepatitis C virus (HCV), and miR-27a can inhibit HCV replication and infection by inhibiting the expression of FASN and SREBP1 [94]; Infection with Singapore Irivirus (SGIV) increases the expression of key enzymes of fatty acid synthesis in vivo and in vitro, such as FASN and SREBP1, and FASN regulates the replication of SGIV by affecting viral gene transcription and protein expression [95]. The gene discussed is SREBF1; the disease is infection.