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In lower eukaryotes, Sir2 serves as a histone deacetylase and is implicated in chromatin silencing, longevity, and genome stability. Here we mutated the Sirt1 gene, a homolog of yeast Sir2, in mice to study its function. We show that a majority of SIRT1 null embryos die between E9.5 and E14.5, displaying altered histone modification, impaired DNA damage(More)
The RUNX transcription factors are important regulators of linage-specific gene expression in major developmental pathways. Recently, we demonstrated that Runx3 is highly expressed in developing cranial and dorsal root ganglia (DRGs). Here we report that within the DRGs, Runx3 is specifically expressed in a subset of neurons, the tyrosine kinase receptor C(More)
Germline mutations of BRCA1 predispose women to breast and ovarian cancers. However, the downstream mediators of BRCA1 function in tumor suppression remain elusive. We found that human BRCA1-associated breast cancers have lower levels of SIRT1 than their normal controls. We further demonstrated that mammary tumors from Brca1 mutant mice have low levels of(More)
Under various conditions, mammals have the ability to maintain serum glucose concentration within a narrow range. SIRT1 plays an important role in regulating gluconeogenesis and fat metabolism; however, the underlying mechanisms remain elusive. Here, we show that SIRT1 forms a complex with FOXO3a and NRF1 on the SIRT6 promoter and positively regulates(More)
Hereditary hemochromatosis, characterized by iron overload in multiple organs, is one of the most common genetic disorders among Caucasians. Hepcidin, which is synthesized in the liver, plays important roles in iron overload syndromes. Here, we show that a Cre-loxP-mediated liver-specific disruption of SMAD4 results in markedly decreased hepcidin expression(More)
The RUNX transcription factors are important regulators of lineage-specific gene expression. RUNX are bifunctional, acting both as activators and repressors of tissue-specific target genes. Recently, we have demonstrated that Runx3 is a neurogenic transcription factor, which regulates development and survival of proprioceptive neurons in dorsal root(More)
Circadian rhythms are intimately linked to cellular metabolism. Specifically, the NAD(+)-dependent deacetylase SIRT1, the founding member of the sirtuin family, contributes to clock function. Whereas SIRT1 exhibits diversity in deacetylation targets and subcellular localization, SIRT6 is the only constitutively chromatin-associated sirtuin and is(More)
Females with germline mutations in BRCA1 are predisposed to develop breast and ovarian cancers. A previous report indicated that BRCA1 colocalizes with and is necessary for the correct localization of XIST, a noncoding RNA that coats the inactive X chromosome (Xi) to mediate formation of facultative heterochromatin. A model emerged from this study(More)
Glucose homeostasis in mammals is mainly regulated by insulin signaling. It was previously shown that SIRT6 mutant mice die before 4 weeks of age, displaying profound abnormalities, including low insulin, hypoglycemia, and premature aging. To investigate mechanisms underlying the pleiotropic phenotypes associated with SIRT6 deficiency, we generated mice(More)
In yeast, Sir2 family proteins (sirtuins) regulate gene silencing, recombination, DNA repair, and aging via histone deacetylation. Most of the seven mammalian sirtuins (Sirt1-Sirt7) have been implicated as NAD(+)-dependent protein deacetylases with targets ranging from transcriptional regulators to metabolic enzymes. We report that neural-specific deletion(More)