Project description:Identification of BLM phosphosites. The experiment is composed by 2 parts: i) identification of BLM phosphosites with DDA method ii) quantification of phosphosites with a targeted method.
Project description:The Bloom syndrome DNA helicase BLM contributes to chromosome stability through its roles in double-strand break repair by homologous recombination and DNA replication fork restart during the replication stress response. Loss of BLM activity leads to Bloom syndrome, which is characterized by extraordinary cancer risk and small stature. Here, we have analyzed the composition of the BLM complex in unperturbed cells and identified a direct physical interaction with the Mcm6 subunit of the minichromosome maintenance (MCM) complex by co-immunopecipitations using endogenous and recombinant proteins as well as two-hybrid analysis.
Project description:BLM protein has been shown to play an important role in homologous recombination (HR) repair. We report that BLM interacts with RAD54 (another HR repair protein) to enhance its chromatin remodeling function. This experiment identifies that BLM gets recruited to different genetic loci even in the absence of damage, possibly along with RAD54 chromatin remodeler.
Project description:We used microarrays to identify differentially expressed genes after DNA-damaging agent bleomycin (BLM) and/or immune inducer 2, 6-dichloroisonicotinic acid (INA) treatment. We focused on those genes that were synergistically induced by co-treatment (BLM+INA). Arabidopsis seedlings were treated with 4 μg/ml BLM and/or low INA (10 μM). There are 4 treatments: control (CK), INA, BLM and BLM+INA. Each treatments have three biological replicates. There are 12 samples in total.
Project description:Transcriptionally active loci are particularly prone to breakage and mounting evidence suggest that DNA Double-Strand Breaks arising in active genes are handled by a dedicated repair pathway, Transcription-Coupled DSB Repair (TC-DSBR), that entails R-loop accumulation and dissolution. Here, we uncovered a function for the Bloom RecQ DNA helicase (BLM) in TC-DSBR in human cells. BLM is recruited in a transcription dependent-manner at DSBs where it fosters resection, RAD51 binding and accurate Homologous Recombination repair. However, in an R-loop dissolution-deficient background, we found that BLM promotes cell death. We report that upon excessive R-loop accumulation, DNA synthesis is enhanced at DSBs, in a anner that depends on BLM and POLD3. Altogether our work unveils a role for BLM at DSBs in active chromatin, and highlights the toxic potential of RNA:DNA hybrids that accumulate at transcription-associated DSBs.
Project description:Background: Pulmonary Fibrosis (PF) is an interstitial lung disease of unknown etiology, characterized by excessive accumulation of extracellular matrix in the lungs, which disrupts the structure and gas exchange of the alveoli. There are only two approved therapies for PF, nintedanib (Nib) and pirfenidone. Therefore, the use of Chinese medicine for PF is attracting attention. Tianlongkechuanling (TL) is an effective Chinese formula that has been applied clinically to alleviate PF, which can enhance lung function and quality of life. Purpose: The potential effects and specific mechanisms of TL have not been fully explored, yet. In the present study, proteomics was performed to explore the therapeutic protein targets of TL on Bleomycin (BLM)-induced Pulmonary Fibrosis. Method: BLM-induced PF mice models were established. Hematoxylineosin staining and Masson staining were used to analyze histopathological changes and collagen deposition. To screen the differential proteins expression between the Control, BLM, BLM+TL and BLM+ Nib (BLM+ Nintedanib) groups, quantitative proteomics was performed using tandem mass tag (TMT) labeling with nanoLC-MS/MS [nano liquid chromatographymass spectrometry]). Changes in the profiles of the expressed proteins were analyzed using the bioinformatics tools Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG). The protein–protein interactions (PPI) were established by STRING. Expressions of α-smooth muscle actin (α-SMA), Collagen I (Col1a1), Fibronectin (Fn1) and enzymes in arginase-ornithine pathway were detected by Western blot or RT-PCR.
Project description:We report for the first time that secretoglobin (SCGB) 3A2, a novel cytokine-like molecule, predominantly expressed in pulmonary airways epithelium, drastically reduced the severity of lung fibrosis using bleomycin-induced mouse model. DNA microarrays were performed using RNAs isolated from mouse lungs in two experiments. In the first experiments, mice were adminitered intravenously SCGB3A2 or PBS once daily for a week, starting on day 14 after BLM administration, and in the second experiments, SCGB3A2 or PBS was administered intravenously for 12 hrs.
Project description:Basal cell carcinomas (BCCs) have relative genomic stability and relatively benign clinical behavior but whether these two are related causally is unknown. To investigate the effects of introducing genomic instability into murine BCCs, we have compared ionizing radiation-induced tumorigenesis in Ptch1+/- mice vs. that in Ptch1+/- mice carrying mutant Blm alleles. We found that BCCs in Ptch1+/- Blmtm3Brd/tm3Brd mice had a trend towards greater genomic instability as measured by array CGH and that these mice developed significantly more microscopic BCCs than did Ptch1+/- Blm+/tm3Brd or Ptch1+/- Blm+/+ mice. The mutant Blm alleles also markedly enhanced the formation of rhabdomyosarcomas (RMS), another cancer to which Ptch1+/- mice and PTCH1+/- (basal cell nevus syndrome) patients are susceptible. Highly recurrent but different copy number changes were associated with the two tumor types and included losses of chromosomes 4 and 10 in all BCCs and gain of chromosome 10 in 80% of RMSs. Loss of chromosome 11 and 13, including the Trp53 and Ptch1 loci respectively, occurred frequently in BCCs, suggesting tissue-specific selection for genes or pathways that collaborate with Ptch deficiency in tumorigenesis. Despite the quantitative differences, there was no dramatic qualitative difference in the BCC or RMS tumors associated with the mutant Blm genotype.
Project description:Basal cell carcinomas (BCCs) have relative genomic stability and relatively benign clinical behavior but whether these two are related causally is unknown. To investigate the effects of introducing genomic instability into murine BCCs, we have compared ionizing radiation-induced tumorigenesis in Ptch1+/- mice vs. that in Ptch1+/- mice carrying mutant Blm alleles. We found that BCCs in Ptch1+/- Blmtm3Brd/tm3Brd mice had a trend towards greater genomic instability as measured by array CGH and that these mice developed significantly more microscopic BCCs than did Ptch1+/- Blm+/tm3Brd or Ptch1+/- Blm+/+ mice. The mutant Blm alleles also markedly enhanced the formation of rhabdomyosarcomas (RMS), another cancer to which Ptch1+/- mice and PTCH1+/- (basal cell nevus syndrome) patients are susceptible. Highly recurrent but different copy number changes were associated with the two tumor types and included losses of chromosomes 4 and 10 in all BCCs and gain of chromosome 10 in 80% of RMSs. Loss of chromosome 11 and 13, including the Trp53 and Ptch1 loci respectively, occurred frequently in BCCs, suggesting tissue-specific selection for genes or pathways that collaborate with Ptch deficiency in tumorigenesis. Despite the quantitative differences, there was no dramatic qualitative difference in the BCC or RMS tumors associated with the mutant Blm genotype. We investigated the effect of Blm deficiency on ionizing radiation-induced basal cell carcinoma and rhabdomyosarcoma tumorigenesis in Ptch1+/- mice. Six BCC and five RMS samples were obtained from separate mice. Liver tissue from each mouse was used as the normal reference.
Project description:Idiopathic pulmonary fibrosis is a chronic devastating disease of unknown etiology. No therapy is currently available. A growing body of evidence supports the role of TGFβ1 as the major player in the pathogenesis of the disease. This study designed novel human- and mouse-specific siRNAs and siRNA/DNA chimeras targeting both human and mouse common sequences and evaluated their inhibitory activity in pulmonary fibrosis induced by bleomycin and lung-specific transgenic expression of human TGFβ1. Selective novel sequences of siRNA and siRNA/DNA chimeras efficiently inhibited pulmonary fibrosis, indicating their applicability as tools for treating fibrotic disease in humans. Total RNA was extracted from lung tissue from mice with bleomycin (BLM)-induced lung fibrosis treated with mouse TGFβ1 siRNAs or vehicle on different days after BLM infusion.