Fig. 3: L1 genotoxicity is ultimately reduced in oocytes independent of piRNAs.

a, b RMN fluorescence γH2AX and L1 ORF1p levels in Chk2^+/− and Chk2^−/− untreated and AZT-treated oocytes at a E18.5 and b P2. Box plots indicate center line at median value, box limits at upper and lower quartile values, and whiskers at max and min values; n > 118 oocytes per sample. Stats by Kolmogorov–Smirnov test, ns p > 0.05; *p < 0.05; ***p < 0.001. c L1 ORF1 mRNA expression in UT and AZT-treated oocytes by qRT-PCR. Normalized to E15.5 UT with Actb internal control. n > 6 WT CD1 embryos from single litter per replicate, each bar represents two biological replicates. Dots indicate individual biological replicates; data are mean + SD. Stats by two-tailed paired Student’s t-test, *p < 0.05. Source data are provided as a Source Data file. d Expression of piRNA biogenesis genes in WT E15.5 and WT E18.5 sorted oocytes of CD1 genetic background. Two biological replicates per stage. e MILI expression in E15.5, E18.5, and P2 ovary sections of WT CD1 mice. Scale bars:15 μm. f Length distribution of 18–32nt small RNA reads from E15.5, E18.5, and P2 WT and P2 Mili^−/− ovaries. g–i Antisense transposon-targeting small RNAs in g E15.5 vs. P2 WT h E18.5 vs. P2 WT and i P2 Mili^+/+ vs. P2 Mili^−/− ovaries. For small RNA-Seq, at least three pairs of ovaries from a single litter used per sample, data represents one biological replicate per sample. Experiment repeated for WT E18.5 and WT P2 conditions (Supplementary Data 4a). j RMN fluorescence L1ORF1p levels in Mili^−/−;Chk2^−/− + AZT and control P2 ovaries. Box plots indicate center line at median value, box limits at upper and lower quartile values, and whiskers at max and min values; n > 127 oocytes per sample. Stats by Kolmogorov–Smirnov test, ns p > 0.05; **p < 0.01. k Oocyte number in Mili^−/−;Chk2^−/− + AZT and control P2 ovaries. Dots indicate independent ovary samples; data are mean + SD; n > 3 ovaries per condition. Stats by two-tailed unpaired Student’s t-test, ns p > 0.05; *p < 0.05.