Figure 1.

De Novo Accumulation of H2A Variants at UVC Damage Sites

(A) Assay for monitoring the accumulation of newly synthesized histones labeled with tetramethylrhodamine (TMR)-star at UVC damage sites marked by the repair factor XPA (xeroderma pigmentosum, complementation group A) in human cells stably expressing SNAP-tagged histones.

(B–E) New histone accumulation at UVC damage sites marked by XPA analyzed 2 hr after irradiation in U2OS cells stably expressing the indicated SNAP-tagged histone variants, wild-type (B–D) and mutants (E).

Cells were treated without (B) or with (C) RNAPII inhibitors (DRB; FLV, flavopiridol; AMA, α-amanitin; DMSO and PBS, vehicles). Total H2A.X is detected by immunostaining for SNAP or H2A.X (D). S139A/E, phospho-deficient/mimetic mutant; WT, wild-type. Bar chart shows mean ± SD from 2 independent experiments. Scale bars, 10 μm.

ns, non-significant; ^∗p < 0.05; ^∗∗p < 0.01; ^∗∗∗p < 0.001. See also Figures S1–S4.