Reduction of hRNase H2 activity in Aicardi-Goutières syndrome cells leads to replication stress and genome instability.
Bottom Line: Our data indicate that in human cells RNase H2 plays a crucial role in correcting rNMPs misincorporation, preventing DNA damage.Such protective function is compromised in AGS patients and may be linked to unscheduled immune responses.These findings may be relevant to shed further light on the mechanisms involved in AGS pathogenesis.
Affiliation: Dipartimento di Bioscienze, Università degli Studi di Milano, 20133 Milano, Italy.Show MeSH
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Mentions: Exponentially growing HeLa cells were labeled with BrdU to mark replicating cells, and analyzed by cytofluorimetry for total DNA content and for active replication. RNase H2 silencing affected cell cycle progression, resulting in a reproducible and significant accumulation of cells in S and G2-M phases (Fig. 2A). Cell cycle progression was further analyzed in a kinetic experiment where cells traversing S-phase were labeled with a pulse of BrdU and followed for 8 h after release in BrdU-free medium. When compared with the SCRAMBLE control, cells depleted for RNase H2 were delayed in late-S/G2 phase and were very slow in getting back into G1 phase (Fig. 2B), indicative of replication problems. Similar results were obtained using MRC5VI cells, indicating that it is not a cell-specific effect (Supplementary Material, Fig. S4A).Figure 2.
Affiliation: Dipartimento di Bioscienze, Università degli Studi di Milano, 20133 Milano, Italy.