Kyu Sang Joeng

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Canonical Wnt signaling critically regulates cell fate and proliferation in development and disease. Nuclear localization of beta-catenin is indispensable for canonical Wnt signaling; however, the mechanisms governing beta-catenin nuclear localization are not well understood. Here we demonstrate that nuclear accumulation of beta-catenin in response to Wnt(More)
This report identifies human skeletal diseases associated with mutations in WNT1. In 10 family members with dominantly inherited, early-onset osteoporosis, we identified a heterozygous missense mutation in WNT1, c.652T→G (p.Cys218Gly). In a separate family with 2 siblings affected by recessive osteogenesis imperfecta, we identified a homozygous nonsense(More)
Telomere length is a crucial factor in senescence, but it has not been determined whether animals with long telomeres live longer than those with normal-length telomeres in the isogenic background of a given species. Here we show the effect of long telomeres on lifespan in the nematode Caenorhabditis elegans. We examined the effect of telomere length on(More)
Wnt signaling regulates a variety of developmental processes in animals. Although the beta-catenin-dependent (canonical) pathway is known to control cell fate, a similar role for noncanonical Wnt signaling has not been established in mammals. Moreover, the intracellular cascades for noncanonical Wnt signaling remain to be elucidated. Here, we delineate a(More)
The role of Wnt signaling in osteoblastogenesis in the embryo remains to be fully established. Although β-catenin, a multifunctional protein also mediating canonical Wnt signaling, is indispensable for embryonic osteoblast differentiation, the roles of the key Wnt co-receptors Lrp5 and Lrp6 are unclear. Indeed, global deletion of either Lrp5 or Lrp6 did not(More)
WNT signaling has been implicated in both embryonic and postnatal bone formation. However, the pertinent WNT ligands and their downstream signaling mechanisms are not well understood. To investigate the osteogenic capacity of WNT7B and WNT5A, both normally expressed in the developing bone, we engineered mouse strains to express either protein in a(More)
The Ihh (Indian Hedgehog) pathway plays an essential role in facilitating chondrocyte hypertrophy and bone formation during skeletal development. Nkx3.2 (NK3 homeobox 2) is initially induced in chondrocyte precursor cells, maintained in early-stage chondrocytes and down-regulated in terminal-stage chondrocytes. Consistent with these expression patterns,(More)
Since the completion of the genome project of the nematode C. elegans in 1998, functional genomic approaches have been applied to elucidate the gene and protein networks in this model organism. The recent completion of the whole genome of C. briggsae, a close sister species of C. elegans, now makes it possible to employ the comparative genomic approaches(More)
Myopia, the leading cause of visual impairment worldwide, results from an increase in the axial length of the eyeball. Mutations in LEPREL1, the gene encoding prolyl 3-hydroxylase-2 (P3H2), have recently been identified in individuals with recessively inherited nonsyndromic severe myopia. P3H2 is a member of a family of genes that includes three isoenzymes(More)
The bone marrow environment is among the most hypoxic in the body, but how hypoxia affects bone formation is not known. Because low oxygen tension stabilizes hypoxia-inducible factor alpha (HIFα) proteins, we have investigated the effect of expressing a stabilized form of HIF1α in osteoblast precursors. Brief stabilization of HIF1α in SP7-positive cells in(More)