Three orthogonal protein degradation screens showing that DMXL1 is degraded with high confidence during early HCMV infection, from Nightingale et al. Left panel: DMXL1 was rescued from degradation by the proteasome inhibitor MG132 in HCMV-infected cells, but not during mock infection, infection with UV-irradiated HCMV (HCMVUV), or inhibition with the lysosomal protease inhibitor leupeptin (see also Figure 1 from Nightingale et al.). Middle panel: increased rate of DMXL1 degradation during HCMV compared with mock infection. Cells were pre-labeled with medium SILAC (stable isotope labelling by amino acids in cell culture) amino acids prior to infection, then switched to heavy amino acids at the point of infection. Quantification of medium-labeled proteins over time using TMT-based multiplexing facilitated quantification of protein degradation rates (see also Figure 2 from Nightingale et al.). Right panel: relative abundance of DMXL1 transcript over 72 h infection. Although DMXL1 protein was not identified in this screen to enable simultaneous quantitation, DMXL1 was downregulated in our other experiments over a comparable time course suggesting that it is degraded (left panels and C; see also Figure 3 from Nightingale et al.).
