Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0002871 (anemia)
 52,094 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Mutations in SMARCAL1 cause Schimke Immuno-Osseous Dysplasia (SIOD), an autosomal recessive multisystem developmental disease characterized by growth retardation, T-cell deficiency, bone marrow failure, anemia and renal failure. SMARCAL1 encodes an ATP-driven annealing helicase. However, the biological function of SMARCAL1 and the molecular basis of SIOD remain largely unclear. In this work, we cloned the zebrafish homologue of the human SMARCAL1 gene and found that smarcal1 regulated cell cycle progression. Morpholino knockdown of smarcal1 in zebrafish recapitulated developmental abnormalities in SIOD patients, including growth retardation, craniofacial abnormality, and haematopoietic and vascular defects. Lack of smarcal1 caused G0/G1 cell cycle arrest and induced cell apoptosis. Furthermore, using Electrophoretic Mobility Shift Assay and reporter assay, we found that SMARCAL1 was transcriptionally inhibited by E2F6, an important cell cycle regulator. Over-expression of E2F6 in zebrafish embryos reduced the expression of smarcal1 mRNA and induced developmental defects similar to those in smarcal1 morphants. These results suggest that SIOD may be caused by defects in cell cycle regulation. Our study provides a model of SIOD and reveals its cellular and molecular bases.
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PMID:Deficiency of smarcal1 causes cell cycle arrest and developmental abnormalities in zebrafish. 2003 29

DNA interstrand cross-links (ICLs) are a form of DNA damage that requires the interplay of a number of repair proteins including those of the Fanconi anemia (FA) and the homologous recombination (HR) pathways. Pathogenic variants in the essential gene BRCA2/FANCD1, when monoallelic, predispose to breast and ovarian cancer, and when biallelic, result in a severe subtype of Fanconi anemia. BRCA2 function in the FA pathway is attributed to its role as a mediator of the RAD51 recombinase in HR repair of programmed DNA double-strand breaks (DSB). BRCA2 and RAD51 functions are also required to protect stalled replication forks from nucleolytic degradation during response to hydroxyurea (HU). While RAD51 has been shown to be necessary in the early steps of ICL repair to prevent aberrant nuclease resection, the role of BRCA2 in this process has not been described. Here, based on the analysis of BRCA2 DNA-binding domain (DBD) mutants (c.8488-1G>A and c.8524C>T) discovered in FA patients presenting with atypical FA-like phenotypes, we establish that BRCA2 is necessary for the protection of DNA at ICLs. Cells carrying BRCA2 DBD mutations are sensitive to ICL-inducing agents but resistant to HU treatment consistent with relatively high HR repair in these cells. BRCA2 function at an ICL protects against DNA2-WRN nuclease-helicase complex and not the MRE11 nuclease that is implicated in the resection of HU-induced stalled replication forks. Our results also indicate that unlike the processing at HU-induced stalled forks, the function of the SNF2 translocases (SMARCAL1, ZRANB3, or HLTF), implicated in fork reversal, are not an integral component of the ICL repair, pointing to a different mechanism of fork protection at different DNA lesions.
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PMID:Distinct roles of BRCA2 in replication fork protection in response to hydroxyurea and DNA interstrand cross-links. 3235 36