Journal: Journal of Virology
Article Title: p21 Restricts HIV-1 in Monocyte-Derived Dendritic Cells through the Reduction of Deoxynucleoside Triphosphate Biosynthesis and Regulation of SAMHD1 Antiviral Activity
Figure Lengend Snippet: Proposed model for p21-mediated HIV-1 restriction in MDDCs. The expression of p21 is induced during MDDC maturation (step 1). The increase in p21 expression leads to the downregulation of several enzymes (RNR2, TYMS, and TK1) involved in dNTP biosynthesis (step 2), which would decrease the dNTP pool size (step 3), impairing HIV-1 reverse transcription (step 4). In parallel, p21 induction could increase the active isoform of SAMHD1 (step 5), which would further block viral replication through the degradation of dNTPs (step 6) or exonuclease activity (step 7). Low levels of dNTP synthesis as a consequence of p21 induction might further facilitate the exonuclease activity of SAMHD1 (step 8). Although not explored here, induction of p21 might also directly block reverse transcriptase activity and impair HIV transcription, as has been shown in CD4 + ).
Article Snippet: PCR amplification of cDNAs was carried out as previously described ( ) on a 7500 real-time PCR system using the TaqMan gene expression premade mix (Applied Biosystems) to amplify the following genes: RRM2 (Hs00357247_g1), TYMS (Hs00426586_m1), SAMHD1 (Hs00210019_m1), CTPS1 (Hs01041858_m1), TK1 (Hs01062125_m1), CDKN1A (Hs00355782_m1), and GAPDH (Hs02758991_g1).
Techniques: Expressing, Blocking Assay, Activity Assay