The C-terminal region (CTR) is vital for the nuclear localization and recruitment of
cattle XLF to DSBs in vivo. (A) Extracts from cattle (MDBK) cells
transiently expressing the indicated cattle XLF deletions were prepared and subjected
to Western blotting using the anti-GFP or anti-β-actin antibody. (B, C) Identification
of essential domain of cattle XLF for nuclear localization and for accumulation at
DSBs. EYFP-cattle XLF mutants were expressed in cattle (MDBK) cells. The localization
and accumulation of the chimeric proteins at laser-induced DSBs were investigated via
live cell imaging. The results are summarized on the right: Cellular localization (N,
nucleus; C, cytoplasm) and formation of focus (+, accumulated at microirradiated
sites; -, not accumulated at microirradiated sites). Arrowheads indicate the
microirradiated sites (C). (D) Immunostaining of microirradiated EYFP-cattle XLF
(162–287)-transfected cells with anti-γH2AX antibody. The cells were fixed and stained
with the anti-γH2AX antibody at 5 min postirradiation. Left panel, EYFP-cattle XLF
(162-287); center panel, γH2AX image; right panel, merged image. (E) Identity between
the cattle XLF and human XLF at the amino acid level and the CTR of cattle XLF (amino
acids 288–299). (F) The alignment of the primary sequence among homologous XLF
proteins. For comparison, the basic (red) or non-basic residues (black) are shown in
different colors. The GeneBank accession number for each sequence is mentioned. *, The
sequence of CTR of chicken XLF is from Reference [1].