Figure 1. Decapping and cap-snatching machinery compete for cell cycle regulated mRNAs. Left: Schematic of P body dynamics during cell cycle progression. During G₁, P bodies (green) are present at low levels in cells. As cells exit S phase and progress into G₂, P bodies increase in number and size.^1,4 As cells enter mitosis, P bodies are lost.⁴ Upper inset: RVFV cap-snatching and Dcp2 mRNA decapping are competing processes. Viral mRNA transcription initiates upon the binding of RVFV N (red circles) to 5′ caps of cellular mRNAs (blue). Next, RVFV L (red moons) is recruited, and its endonuclease activity cleaves 10–18bp downstream of the cap and uses this primer to initiate viral transcription from the genomic RNA (black line), producing cellular-virus conjugate mRNAs (blue and red line). Dcp2 (orange) targets and degrades the same pool of cellular mRNAs that RVFV uses for transcription, creating a bottleneck. Lower inset: During the S/G₂ phase of the cell cycle, as mRNAs required for DNA replication are targeted for degradation (blue), this increased level of substrates alleviates the bottleneck, allowing the viral cap-snatching machinery to increase viral transcription (blue and red lines). Thus, arresting cells in S/G₂ increases bunyaviral replication.