Recent findings have highlighted roles played by innate cellular factors in restricting intracellular viral replication. In this review, we discuss in brief the activities of apolipoprotein B mRNA-editing enzyme 3G (APOBEC3G), bone marrow stromal cell antigen 2 (BST-2), cyclophilin A, tripartite motif protein 5 alpha (Trim5alpha), and cellular microRNAs as examples of host restriction factors t...

APOBEC3A and APOBEC3G cytidine deaminases inhibit viruses and endogenous retrotransposons. We recently demonstrated the novel cellular C-to-U RNA editing function of APOBEC3A and APOBEC3G. Both enzymes deaminate single-stranded DNAs at multiple TC or CC nucleotide sequences, but edit only a select set of RNAs, often at a single TC or CC nucleotide sequence. To examine the specific site preferen...

Human endogenous retroviruses (HERVs) comprise approximately 8% of the human genome, but all are remnants of ancient retroviral infections and harbor inactivating mutations that render them replication defective. Nevertheless, as viral "fossils," HERVs may provide insights into ancient retrovirus-host interactions and their evolution. Indeed, one endogenous retrovirus [HERV-K(HML-2)], which has...

Increasing evidence indicates that the host range of primate lentiviruses is in part determined by their ability to counteract innate restriction factors that are effectors of the type 1 interferon (IFN-1) response. For human immunodeficiency virus type 1 (HIV-1), in vitro experiments have shown that its tropism may be narrow and limited to humans and chimpanzees because its replication in othe...

BACKGROUND During pregnancy, the placenta may become exposed to micro-organisms, such as viruses, which may pose a substantial threat to the embryo/fetus well-being. Recent insight into the immunological capabilities of the trophoblast suggests that the placenta may function as an active barrier by recognizing and responding to pathogens through Toll-like receptors (TLRs). METHODS The objecti...