RESUMO
The assembly of transcription complexes on eukaryotic promoters involves a series of steps, including chromatin remodeling, recruitment of TATA-binding protein (TBP)-containing complexes, the RNA polymerase II holoenzyme, and additional basal transcription factors. This review describes the transcriptional regulation by TBP and its corresponding homologs that constitute the TBP family and their interactions with promoter DNA. The C-terminal core domain of TBP is highly conserved and contains two structural repeats that fold into a saddle-like structure, essential for the interaction with the TATA-box on DNA. Based on the TBP C-terminal core domain similarity, three TBP-related factors (TRFs) or TBP-like factors (TBPLs) have been discovered in metazoans, TRF1, TBPL1, and TBPL2. TBP is autoregulated, and once bound to DNA, repressors such as Mot1 induce TBP to dissociate, while other factors such as NC2 and the NOT complex convert the active TBP/DNA complex into inactive, negatively regulating TBP. TFIIA antagonizes the TBP repressors but may be effective only in conjunction with the RNA polymerase II holoenzyme recruitment to the promoter by promoter-bound activators. TRF1 has been discovered inDrosophila melanogasterandAnophelesbut found absent in vertebrates and yeast. TBPL1 cannot bind to the TATA-box; instead, TBPL1 prefers binding to TATA-less promoters. However, TBPL1 shows a stronger association with TFIIA than TBP. The TCT core promoter element is present in most ribosomal protein genes inDrosophilaand humans, and TBPL1 is required for the transcription of these genes. TBP directly participates in the DNA repair mechanism, and TBPL1 mediates cell cycle arrest and apoptosis. TBPL2 is closely related to its TBP paralog, showing 95% sequence similarity with the TBP core domain. Like TBP, TBPL2 also binds to the TATA-box and shows interactions with TFIIA, TFIIB, and other basal transcription factors. Despite these advances, much remains to be explored in this family of transcription factors.
Assuntos
RNA Polimerase II , Proteína de Ligação a TATA-Box , Fatores de Transcrição , Transcrição Gênica , Adenosina Trifosfatases/genética , Animais , DNA/genética , Drosophila , Holoenzimas/genética , Holoenzimas/metabolismo , Humanos , Proteínas Nucleares/genética , RNA Polimerase II/genética , RNA Polimerase II/metabolismo , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae , TATA Box/genética , Proteínas Semelhantes à Proteína de Ligação a TATA-Box/química , Proteínas Semelhantes à Proteína de Ligação a TATA-Box/genética , Proteínas Semelhantes à Proteína de Ligação a TATA-Box/metabolismo , Fatores Associados à Proteína de Ligação a TATA , Proteína de Ligação a TATA-Box/química , Proteína de Ligação a TATA-Box/genética , Proteína de Ligação a TATA-Box/metabolismo , Fator de Transcrição TFIIA/genética , Fator de Transcrição TFIIA/metabolismo , Fatores de Transcrição/genéticaRESUMO
BACKGROUND: Poly-(ADP-Ribose)-Polymerase inhibitors (PARPi) were reported as radiosensitizers in non-small cell lung cancer (NSCLC) with wide-type epidermal growth factor receptor (EGFR), but the effects of radiation combined with PARPi were not investigated in EGFR-mutated NSCLC. Moreover, the underlying mechanisms were not well examined. This study aimed to study the efficacy of radiation combined with niraparib in EGFR-mutated NSCLC and explore their influence on the immune system. METHODS: Clone formation and apoptosis assay were conducted to explore the effects of niraparib and radiation. Immunofluorescence was conducted to detect the double-strand DNA breaks. Real-time PCR and immunoblotting were employed to evaluate the activation of STING/TBK1/TRF3 pathway and the expression levels of interferon ß, CCL5 and CXCL10. Immunocompetent mice model bearing with subcutaneous Lewis lung cancer was established to confirm the results in vivo. RESULTS: Niraparib and radiation were synergistic to inhibit tumor both in vitro and in vivo. Radiation plus niraparib could activate anti-tumor immunity, which appeared as increased CD8+ T lymphocytes and activated STING/TBK1/IRF3 pathway. CONCLUSION: PARPi not only as a radiosensitizer inhibited EGFR-mutated NSCLC tumor growth, but also cooperated with radiation to promote anti-tumor immune responses.
Assuntos
Carcinoma Pulmonar de Células não Pequenas/terapia , Quimiorradioterapia/métodos , Genes erbB-1 , Indazóis/farmacologia , Neoplasias Pulmonares/terapia , Mutação , Piperidinas/farmacologia , Inibidores de Poli(ADP-Ribose) Polimerases/farmacologia , Radiossensibilizantes/farmacologia , Animais , Linfócitos T CD8-Positivos , Carcinoma Pulmonar de Lewis/imunologia , Carcinoma Pulmonar de Lewis/terapia , Carcinoma Pulmonar de Células não Pequenas/imunologia , Carcinoma Pulmonar de Células não Pequenas/mortalidade , Linhagem Celular Tumoral , Quimiocina CCL5/metabolismo , Quimiocina CXCL10/metabolismo , Quebras de DNA de Cadeia Dupla , Feminino , Imunofluorescência , Humanos , Sistema Imunitário/efeitos dos fármacos , Sistema Imunitário/efeitos da radiação , Imunocompetência , Fator Regulador 3 de Interferon/metabolismo , Interferon beta/metabolismo , Neoplasias Pulmonares/imunologia , Neoplasias Pulmonares/mortalidade , Linfócitos do Interstício Tumoral , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Proteínas Nucleares/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Tolerância a Radiação/efeitos dos fármacos , Reação em Cadeia da Polimerase em Tempo Real , Proteínas Semelhantes à Proteína de Ligação a TATA-Box/metabolismo , Ensaio Tumoral de Célula-TroncoRESUMO
Muscle injuries are the most prevalent type of injury in sports. A great number of athletes have relapsed in muscle injuries not being treated properly. Photobiomodulation therapy is an inexpensive and safe technique with many benefits in muscle injury treatment. However, little has been explored about the infrared laser effects on DNA and telomeres in muscle injuries. Thus, the aim of this study was to evaluate photobiomodulation effects on mRNA relative levels from genes related to telomere and genomic stabilization in injured muscle. Wistar male rats were randomly divided into six groups: control, laser 25 mW, laser 75 mW, injury, injury laser 25 mW, and injury laser 75 mW. Photobiomodulation was performed with 904 nm, 3 J/cm2 at 25 or 75 mW. Cryoinjury was induced by two applications of a metal probe cooled in liquid nitrogen directly on the tibialis anterior muscle. After euthanasia, skeletal muscle samples were withdrawn and total RNA extracted for evaluation of mRNA levels from genomic (ATM and p53) and chromosome stabilization (TRF1 and TRF2) genes by real-time quantitative polymerization chain reaction. Data show that photobiomodulation reduces the mRNA levels from ATM and p53, as well reduces mRNA levels from TRF1 and TRF2 at 25 and 75 mW in injured skeletal muscle. In conclusion, photobiomodulation alters mRNA relative levels from genes related to genomic and telomere stabilization in injured skeletal muscle.
Assuntos
Cromossomos de Mamíferos/genética , Genoma , Terapia com Luz de Baixa Intensidade/métodos , Músculo Esquelético/lesões , Músculo Esquelético/efeitos da radiação , Animais , Proteínas Mutadas de Ataxia Telangiectasia/genética , Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Masculino , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ratos Wistar , Proteínas Semelhantes à Proteína de Ligação a TATA-Box/genética , Proteínas Semelhantes à Proteína de Ligação a TATA-Box/metabolismo , Proteína 1 de Ligação a Repetições Teloméricas/genética , Proteína 1 de Ligação a Repetições Teloméricas/metabolismo , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismoRESUMO
Entamoeba histolytica is the protozoan parasite which causes human amoebiasis. In this parasite, few encoding genes for transcription factors have been cloned and characterized. The E. histolytica TATA-box binding protein (EhTBP) is the first basal transcription factor that has been studied. To continue with the identification of other members of the basal transcription machinery, we performed an in silico analysis of the E. histolytica genome and found three loci encoding for polypeptides with similarity to EhTBP. One locus has a 100% identity to the previously Ehtbp gene reported by our group. The second locus encodes for a 212 aa polypeptide that is 100% identical to residues 23-234 from EhTBP. The third one encodes for a 216 aa polypeptide of 24kDa that showed 42.6% identity and 73.7% similarity to EhTBP. This protein was named E. histolytica TBP-related factor 1 (EhTRF1). Ehtrf1 gene was expressed in bacteria and the purified 28kDa recombinant polypeptide showed the capacity to bind to TATTTAAA-box by electrophoretic mobility shift assays. K(D) values for rEhTBP and rEhTRF1 were (1.71+/-2.90)x10(-12)M and (1.12+/-0.160)x10(-11)M, respectively. Homology modeling of EhTRF1 and EhTBP revealed that, although they were very similar, they showed some differences on their surfaces. Thus, E. histolytica is a unicellular organism having two members of the TBP family.