The essential components of splicing are the splicing factors accumulated in nuclear speckles; thus, we studied how DNA damaging agents and A-type lamin depletion affect the properties of these regions, positive on the SC-35 protein. We observed that inhibitor of PARP (poly (ADP-ribose) polymerase), and more pronouncedly inhibitors of RNA polymerases, caused DNA damage and increased the SC35 protein level. Interestingly, nuclear blebs, induced by PARP inhibitor and observed in A-type lamin-depleted or senescent cells, were positive on both the SC-35 protein and another component of the spliceosome, SRRM2. In the interphase cell nuclei, SC-35 interacted with the phosphorylated form of RNAP II, which was A-type lamin-dependent. In mitotic cells, especially in telophase, the SC35 protein formed a well-visible ring in the cytoplasmic fraction and colocalized with β-catenin, associated with the plasma membrane. The antibody against the SRRM2 protein showed that nuclear speckles are already established in the cytoplasm of the late telophase and at the stage of early cytokinesis. In addition, we observed the occurrence of splicing factors in the nuclear blebs and micronuclei, which are also sites of both transcription and splicing. This conclusion supports the fact that splicing proceeds transcriptionally. According to our data, this process is A-type lamin-dependent. Lamin depletion also reduces the interaction between SC35 and β-catenin in mitotic cells.

• Klíčová slova
• PARP inhibitor, RNA pol II, SC-35, splicing,
• MeSH
• HeLa buňky MeSH
• laminy metabolismus   MeSH
• lidé MeSH
• nádorové buněčné linie MeSH
• PARP inhibitory terapeutické užití   MeSH
• poly-ADP-ribóza-polymeráza 1 MeSH
• RNA-polymerasa II metabolismus   MeSH
• sestřihové faktory metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• laminy MeSH
• PARP inhibitory MeSH
• PARP1 protein, human MeSH Prohlížeč
• poly-ADP-ribóza-polymeráza 1 MeSH
• RNA-polymerasa II MeSH
• sestřihové faktory MeSH

Methylation of histones H4 at lysine 20 position (H4K20me), which is functional in DNA repair, represents a binding site for the 53BP1 protein. Here, we show a radiation-induced increase in the level of H4K20me3 while the levels of H4K20me1 and H4K20me2 remained intact. H4K20me3 was significantly pronounced at DNA lesions in only the G1 phase of the cycle, while this histone mark was reduced in very late S and G2 phases when PCNA was recruited to locally micro-irradiated chromatin. H4K20me3 was diminished in locally irradiated Suv39h1/h2 double knockout (dn) fibroblasts, and the same phenomenon was observed for H3K9me3 and its binding partner, the HP1β protein. Immunoprecipitation showed the existence of an interaction between H3K9me3-53BP1 and H4K20me3-53BP1; however, HP1β did not interact with 53BP1. Together, H3K9me3 and H4K20me3 represent epigenetic markers that are important for the function of the 53BP1 protein in non-homologous end joining (NHEJ) repair. The very late S phase represents the cell cycle breakpoint when a DDR function of the H4K20me3-53BP1 complex is abrogated due to recruitment of the PCNA protein and other DNA repair factors of homologous recombination to DNA lesions.

• Klíčová slova
• DNA damage, H3K9me3, H4K20me1/me2/me3, Suv39h1/h2, epigenetics,
• MeSH
• 53BP1 genetika   metabolismus   MeSH
• buněčné jádro genetika   metabolismus   účinky záření   MeSH
• buněčné linie MeSH
• buněčný cyklus MeSH
• chromozomální proteiny, nehistonové metabolismus   MeSH
• epigeneze genetická * účinky záření   MeSH
• histony metabolismus   MeSH
• homolog proteinu s chromoboxem 5 MeSH
• lidé MeSH
• metylace DNA * účinky záření   MeSH
• metylace MeSH
• myši MeSH
• oprava DNA spojením konců * MeSH
• poškození DNA * MeSH
• proliferační antigen buněčného jádra metabolismus   MeSH
• restrukturace chromatinu MeSH
• vazba proteinů MeSH
• vazebná místa MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 53BP1 MeSH
• CBX1 protein, human MeSH Prohlížeč
• Cbx1 protein, mouse MeSH Prohlížeč
• chromozomální proteiny, nehistonové MeSH
• histony MeSH
• homolog proteinu s chromoboxem 5 MeSH
• PCNA protein, human MeSH Prohlížeč
• proliferační antigen buněčného jádra MeSH
• TP53BP1 protein, human MeSH Prohlížeč
• Trp53bp1 protein, mouse MeSH Prohlížeč

• Publikační typ
• úvodníky MeSH