Blockade of <i>de novo</i> dNTP biosynthesis pathway delays HIV-1 early life cycle kinetics and dynamics

Cellular dNTP pool homeostasis is maintained by the interplay between the biosynthetic (<i>de novo</i> and salvage) pathways and hydrolyzing networks such as SAMHD1. Inhibiting <i>de novo</i> pathway using RNR inhibitors reduces the host cell dNTP pool size, thereby restricting HIV-1 infectivity reversibly. Whereas the salvage pathways cannot rescue HIV-1 infectivity to the full extent without the <i>de novo</i> pathway. This work correlates HIV-1 infectivity with the dynamic nature of dNTP turnover due to RNR small subunit switching between RRM2 & RRM2B and the action of SAMHD1. The observed modulation of HIV-1 reverse transcription and uncoating in response to RNR inhibition demonstrates the flexibility and adaptability of the virus to replicate in hostile internal cellular environments, which attempt to starve the virus of essential metabolites such as dNTPs. These findings provide insights into how RNR inhibition may impact subsequent steps, such as nuclear localization and integration, offering a foundation for future studies.