Files in this Data Supplement:

• Supplemental file 1 - Tables S1 (Frequency of viable progeny from crosses between Ercc1^+/- Ku86^+/- and Ercc1^+/Δ Ku86^+/- mice), S2 (Frequency of Ercc1^-/- Ku86^-/- embryos from crosses between Ercc1^+/- Ku86^+/- mice), and S3 to S5 (Nucleotide sequences of junctions from DNA substrates with blunt [S3], compatible [S4], and noncompatible [S5] ends after joining in the wt and Ercc1^-/- cells).
  PDF file 56K.
• Supplemental file 2 - Fig. S1 (Clonogenic survival assays).
  PDF file 41K.
• Supplemental file 3 - Fig. S2 (Immunostaining for γH2AX).
  PDF file, 3.8MB.
• Supplemental file 4 - Fig. S3 (Ki67 immunostaining of small intestine).
  PDF file 6.1MB.
• Supplemental file 5 - Fig. S4 (Cultures of wt, Ercc1, Ku86, and Ercc1 Ku86 primary MEFs).
  PDF file 212K.
• Supplemental file 6 - Fig. S5 (DSB repair of a linear plasmid).
  PDF file 34K.