Las af 1.8.1 leica

Protein localization was carried out by fluorescence microscopy. For this purpose, cells were grown on coverslips, transfected and fixed in 3.7% formaldehyde solution (47608; Fluka, Sigma, St. Louis, USA) at room temperature for 15 min. After washing with 1x PBS, cells were permeabilized with 0.2% Triton X-100 in PBS and blocked with 10% horse serum before overnight incubation with γ-H2A.X, 53BP1, p-ATM, p-CHK2 antibodies. Finally, cells were washed and incubated with secondary antibodies coupled to fluorescent dyes (alexa fluor 488 or/and alexa fluor 647).
For immuno-FISH, immunostaining of 53BP1 was performed as described above and followed by incubation in PBS 0,1% Triton X-100, fixation 5 min in 2% paraformaldehyde (PFA), dehydration with ethanol and air-dried. Cells were hybridized with the telomeric PNA-Cy3 probe (PNA Bio) using standard PNA-FISH procedures. Imaging was carried out at room temperature in Vectashield, mounting medium for fluorescence (Vector Laboratories, Burlingame, USA). Images were acquired with a Confocal Spectral Leica TCS SP5. Using a HCX PL APO Lambda blue 63×1.40 OIL UV, zoom 2.3 lens. Images were acquired using LAS-AF 1.8.1 Leica software and processed using LAS-AF 1.8.1 Leica software and Adobe Photoshop CS. Colocalization of 53BP1 foci and the PNA FISH probe was quantified in at least 200 cells.

Cells were grown onto 8 mm diameter coverslips, transfected and fixed in 3.7% formaldehyde solution (47608, Fluka, Loughborough, UK) at room temperature for 15 min. After washing with PBS, cells were permeabilized with 0.2% Triton X-100 and blocked with 10% horse serum to prevent non-specific staining. The primary antibody was then added to the blocking buffer and the cells incubated overnight at 4 °C. Primary antibodies: Mouse anti-γ-catenin (610254, BD Transduction), mouse anti–p120 (P17920, BD Biosciences), mouse anti-α-tubulin (T9026, Sigma-Aldrich), and E-cadherin (ECCD2, Zymed laboratories). The day after, the cells were washed in PBS with 0.1% Triton X-100 for three times and incubated with Alexa 546 goat anti-mouse, Alexa 647 goat anti-mouse, (Molecular Probes, Eugene, OR, USA) fluorophore conjugated secondary antibodies for signal detection. The actin filaments were stained using Alexa 546-conjugated phalloidin (Molecular Probes) added after the blocking step. After washes in PBS with 0.1% triton, coverslips were counterstained with 4′,6-diamidino-2-phenylindole (DAPI) and mounted in Prolong Gold Antifade Reagent (Molecular Probes). The micrographs were obtained at Confocal Spectral Leica TCS SP5 and LAS-AF 1.8.1 Leica software.