Project description:The twenty-three Fanconi Anemia proteins cooperate in a DNA repair pathway, called the FA/BRCA pathway, required for the monoubiquitination of FANCD2 and the excision of interstrand DNA crosslinks (ICLs). The CCAR1 (cell division cycle and apoptosis regulator 1) protein is also a regulator of ICL repair, though its possible function in the FA/BRCA pathway remains unknown. Here, we demonstrate that CCAR1 plays a unique upstream role in the FA/BRCA pathway and is required for FANCA protein expression and FANCD2 monoubiquitination. Interestingly, loss of CCAR1 results in retention of a poison exon in the FANCA transcript, thereby leading to reduced FANCA protein expression. A unique domain of CCAR1, the so-called EF-hand domain, binds to the spliceosome SF3B complex and is required for its mRNA splicing activity. Taken together, CCAR1 is a unique splicing factor, required for normal splicing of the FANCA mRNA and perhaps other mRNAs involved in various cellular pathways.
Project description:The NEIL3 DNA glycosylase is a base excision repair enzyme that excises bulky base lesions from DNA. Although NEIL3 has been shown to unhook interstrand crosslinks (ICL) in Xenopus extracts, how NEIL3 participants in ICL repair in human cells and its corporation with the canonical Fanconi anemia (FA)/BRCA pathway remain unclear. Here we show that the NEIL3 and the FA/BRCA pathways are non-epistatic in psoralen-ICL repair. The NEIL3 pathway is the major pathway for repairing psoralen-ICL, and the FA/BRCA pathway is only activated when NEIL3 is not present. Mechanistically, NEIL3 is recruited to psoralen-ICL in a rapid, PARP-dependent manner. Importantly, the NEIL3 pathway repairs psoralen-ICLs without generating double-strand breaks (DSBs), unlike the FA/BRCA pathway. In addition, we found that the RUVBL1/2 complex physically interact with NEIL3 and function within the NEIL3 pathway in psoralen-ICL repair. Moreover, TRAIP is important for the recruitment of NEIL3 but not FANCD2, and knockdown of TRAIP promotes FA/BRCA pathway activation. Interestingly, TRAIP is non-epistatic with both NEIL3 and FA pathways in psoralen-ICL repair, suggesting that TRAIP may function upstream of the two pathways. Taken together, the NEIL3 pathway is the major pathway to repair psoralen-ICL through a unique DSB-free mechanism in human cells.
Project description:The twenty-three Fanconi anemia (FA) proteins cooperate in the FA/BRCA pathway to repair DNA interstrand cross-links (ICLs). The cell division cycle and apoptosis regulator 1 (CCAR1) protein is also a regulator of ICL repair, though its possible function in the FA/BRCA pathway remains unknown. Here, we demonstrate that CCAR1 plays a unique upstream role in the FA/BRCA pathway and is required for FANCA protein expression in human cells. Interestingly, CCAR1 co-immunoprecipitates with FANCA pre-mRNA and is required for FANCA mRNA processing. Loss of CCAR1 results in retention of a poison exon in the FANCA transcript, thereby leading to reduced FANCA protein expression. A unique domain of CCAR1, the EF hand domain, is required for interaction with the U2AF heterodimer of the spliceosome and for excision of the poison exon. Taken together, CCAR1 is a splicing modulator required for normal splicing of the FANCA mRNA and other mRNAs involved in various cellular pathways.
Project description:Fanconi anemia (FA) is a rare inherited disease complicated by aplastic anemia. There is evidence that hematopoietic stem cells have lost self replicative capacity and undergo apoptosis when exposed to inhibitory cytokines including interferon gamma and tumor necrosis factor-alpha. We used gene expression microarrays to identify transcriptomal differences between bone marrow cells from normal volunteers and from children and adults with Fanconi anemia
Project description:Fanconi anemia is a rare inherited hematological disorder which commonly presents with bone marrow failure, developmental abnormalities and susceptibility to cancer with high rates of prevalence in ethnic populations. The objective of this study was to identify potential genes that aid in the progression of the disease or produce its principal symptoms and to hypothesize enabling roles for certain genes that are not part of the central molecular machinery causing the disease. A total of 2 Fanconi anemia samples were collected from patients who displayed characteristic FA features. All of them gave positive results for the DNA breakage test after mitomycin C treatment. Samples were referred by Dr. Sheila Mohan of REFAIN (Registry for Fanconi anemia in India). Whole genome microarray analysis of peripheral blood from 2 patient samples and one normal individual. Sequential analysis of microarray data was carried out using gene ontology and pathway analysis to identify candidate genes.
Project description:Fanconi anemia (FA) is a rare inherited disease complicated by aplastic anemia. There is evidence that hematopoietic stem cells have lost self replicative capacity and undergo apoptosis when exposed to inhibitory cytokines including interferon gamma and tumor necrosis factor-alpha. We used gene expression microarrays to identify transcriptomal differences between bone marrow cells from normal volunteers and from children and adults with Fanconi anemia Experiment Overall Design: Fanconi anemia patients were identified using mitomycin C and/or diepoxybutane chromosomal breakage analysis. Eleven normal volunteers and 21 FA patients were studied. All FA patients with cytogenetic evidence of clonal evolution were excluded. All FA patients with acute leukemia were excluded. RNA was prepared from freshly obtained low density mononuclear cell fractions.
Project description:The effect of gene therapy in the Hematopoietic stem cells of patients with fanconi anemia has been analyzed. For this purpose 3 fanconi patients bone marrow and a healthy one has been aspirated and CD34+ cells sorted. The data was processed using the usual 10X protocol