Apobec proteins

Gripon P, Cannie I, Urban S (2005). EfScient inhibition of hepatitis B virus infection by acylated peptides derived from the large viral surface protein. J Virol 79 1613-1622 Harris RS, Liddament MT (2004) Retroviral restriction by APOBEC proteins. Nat Rev Immunol 4 868-877... 

Human Apobec Protein Family of Nucleic Acid Deaminases ... 

Fig. 5.1 Regulators of pre- and post-integration latency. Pre-integration latency is regulated as the viral RNA is reverse transcribed into the proviral DNA (A). This is controlled by the avaUabdity of the nucleotide pool, half life of the forming proviral cDNA copy, and the interaction of the viral protein Vif with the cellular antiviral protein APOBEC, espedaUy family members 3G and 3R It is also regulated at the step of transport across the nuclear membrane through the availability of ATP as the process requires energy (B). Post-integration, the proviral DNA copy of the viral genome, is regulated maiiily by the avadabdity of host transcription factors, especially NF-kB and NFAT (C)...

Apobec-1 is highly homologous to other cytidine deaminases but does not by itself edit the RNA. Rather, apobec-1 is the catalytic subunit of a multi-protein complex. Apo B48 is generated only in tissues that express apobec-1 mRNA. However, apobec-1 is also expressed in some tissues that do not synthesize apo B mRNA, suggesting additional substrates for this deaminase. Interestingly, transgenic mice that over-express apobec-1 develop hepatocellular carcinomas and liver dysplasia (T.L. Innerarity, 1997). 

AID is homologous to the mRNA editing enzyme Apobec-1 (Table 1), sharing 34% amino acid identity (Muramatsu et al, 1999 Navaratnam et al, 1993). Analyses of human genomic and EST data have revealed several proteins with sequence homology to zinc-dependent deaminase domain... 

---