Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
11
pubmed:dateCreated
2009-11-5
pubmed:abstractText
Runx2 controls the commitment of mesenchymal cells to the osteoblastic lineage. Distinct promoters, designated P1 and P2, give rise to functionally similar Runx2-II and Runx2-I isoforms. We postulate that this dual promoter gene structure permits temporal and spatial adjustments in the amount of Runx2 isoforms necessary for optimal bone development. To evaluate the gene dose-dependent effect of Runx2 isoforms on bone development, we intercrossed selective Runx2-II(+/-) with nonselective Runx2-II(+/-)/Runx2-I(+/-) mice to create compound mutant mice: Runx2-II(+/-), Runx2-II(+/-)/Runx2-I(+/-), Runx2-II(-/-), Runx2-II(-/-)/Runx2-I(+/-), Runx2-II(-/-)/Runx2-I(-/-). Analysis of the different Runx2-deficient genotypes showed gene dose-dependent differences in the level of expression of the Runx2 isoforms. In addition, we found that Runx2-I is predominately expressed in the perichondrium and proliferating chondrocytes, whereas Runx2-II is expressed in hypertrophic chondrocytes and metaphyseal osteoblasts. Newborn mice showed impaired development of a mineralized skeleton, bone length, and widening of the hypertrophic zone that were proportionate to the reduction in total Runx2 protein expression. Osteoblast differentiation ex vivo was also proportionate to total amount of Runx2 expression that correlated with reduced Runx2 binding to the osteocalcin promoter by quantitative chromatin immunoprecipitation analysis. Functional analysis of P1 and P2 promoters showed differential regulation of the two promoters in osteoblastic cell lines. These findings support the possibility that the total amount of Runx2 derived from two isoforms and the P1 and P2 promoters, by regulating the time, place, and amount of Runx2 in response to changing environmental cues, impacts on bone development.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
1523-4681
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
24
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1889-904
pubmed:dateRevised
2010-11-2
pubmed:meshHeading
pubmed-meshheading:19419310-Alkaline Phosphatase, pubmed-meshheading:19419310-Animals, pubmed-meshheading:19419310-Body Weight, pubmed-meshheading:19419310-Bone Development, pubmed-meshheading:19419310-Bone and Bones, pubmed-meshheading:19419310-Calcium, pubmed-meshheading:19419310-Chromatin Immunoprecipitation, pubmed-meshheading:19419310-Core Binding Factor Alpha 1 Subunit, pubmed-meshheading:19419310-Embryo, Mammalian, pubmed-meshheading:19419310-Gene Dosage, pubmed-meshheading:19419310-Gene Expression Profiling, pubmed-meshheading:19419310-Gene Expression Regulation, Developmental, pubmed-meshheading:19419310-Homeostasis, pubmed-meshheading:19419310-Mice, pubmed-meshheading:19419310-Osteoblasts, pubmed-meshheading:19419310-Osteocalcin, pubmed-meshheading:19419310-Promoter Regions, Genetic, pubmed-meshheading:19419310-Protein Binding, pubmed-meshheading:19419310-Protein Isoforms, pubmed-meshheading:19419310-Time Factors, pubmed-meshheading:19419310-X-Ray Microtomography
pubmed:year
2009
pubmed:articleTitle
Dose-dependent effects of Runx2 on bone development.
pubmed:affiliation
Kidney Institute, University of Kansas Medical Center, Kansas City, Kansas, USA.
pubmed:publicationType
Journal Article, Research Support, N.I.H., Extramural