bluuebunny/crossref_metadata_2025_split huggingface dataset:
BMP-2 Gene Polymorphisms and Osteoporosis: The Rotterdam Study
Authors: Medici Marco , van Meurs Joyce BJ , Rivadeneira Fernando , Zhao HongYan , Arp Pascal P , Hofman Albert , Pols Huibert AP , Uitterlinden André G 
Published: June 2006

Abstract
After reported associations of variations in the BMP-2 gene with osteoporosis in small populations, we studied the association of the BMP-2 gene polymorphisms Ser37Ala and Arg190Ser with osteoporosis in 6353 men and women from the Rotterdam Study. We did not observe an association of these variants with BMD, bone loss, hip structural analysis parameters, and fracture risk.
Introduction: Bone morphogenetic protein 2 (BMP-2) plays a role in osteoblast differentiation. BMP-2 gene variation has previously been associated with osteoporosis in various small populations, but current evidence remains inconclusive about the exact association with osteoporosis. Therefore, we studied the association of two polymorphisms located in the BMP-2 gene (Ser37Ala and Arg190Ser) and haplotypes defined by these polymorphisms with BMD, rates of bone loss, parameters of hip structural analysis (HSA), and fractures in the Rotterdam Study, a large prospective cohort study of diseases in the elderly.
Materials and Methods: Databases were searched for polymorphisms and haplotype blocks in the BMP-2 gene region. Allele frequencies for Ser37Ala and Arg190Ser were determined in 60 blacks and 110 Chinese from Coriell panels. Genotype data on Ser37Ala and Arg190Ser were available for 6353 individuals from the Rotterdam Study population. Haplotype alleles defined by Ser37Ala and Arg190Ser were inferred using PHASE software. Genotype and haplotype analyses for BMD (measured at the lumbar spine and femoral neck), bone loss per year (measured at the femoral neck), and HSA were performed using AN(C)OVA. Fractures were analyzed using a Cox proportional-hazards model and logistic regression. All outcomes were adjusted for age, height, and weight.
Results: Allele frequencies were 2.5% for Ala37 and 40.2% for Ser190, whereas haplotype allele frequencies were 57.28% (Ser37Arg190), 40.19% (Ser37Ser190), 2.50% (Ala37Arg190), and 0.02% (Ala37Ser190). For BMD, bone loss, HSA outcomes, and (incident) fractures, no differences could be seen between genotype and haplotype groups.
Conclusions: In this large population-based cohort of Dutch whites, we conclude that the BMP-2 Ser37Ala and Arg190Ser polymorphisms or haplotypes thereof are not associated with parameters of osteoporosis.
Fibroblast Growth Factor-2 Is an Immediate-Early Gene Induced by Mechanical Stress in Osteogenic Cells
Authors: Li Chai-Fei , Hughes-Fulford Millie 
Published: June 2006

Abstract
Fifteen minutes of physiological MS induces FGF-2 in osteogenic cells. Here, we show that MS induced proliferation in both MC3T3-E1 and BMOp cells isolated from Fgf2+/+ mice; Fgf2−/− BMOp cells required exogenous FGF-2 for a normal proliferation response. The induction of fgf-2 is mediated by PKA and ERK pathways.
Introduction: Mechanical stress (MS) induces gene expression and proliferation of osteogenic MC3T3-E1 cells. We have previously shown that physiological levels of MS in MC3T3-E1 cells causes extracellular signal–regulated kinase (ERK)1/2 phosphorylation. Here we evaluate the induction and importance of fibroblast growth factor-2 (FGF-2) for MS-induced proliferation.
Materials and Methods: We characterized the MS induction of fgf-2 using a 15-minute pulse of 120 μstrain and studied the stability of fgf-2 message using actinomycin D. Bone marrow stromal cells (BMOp) isolated from Fgf2−/− and Fgf2+/+ mice were used to study the importance of FGF-2 in MS-induced proliferation.
Results: We found that the induction of fgf-2 by MS is dependent on both protein kinase A (PKA) and ERK pathways. MS transiently induces fgf-2 within 30 minutes. FGF-2 receptor (FGFR2) was also significantly increased within 1 h. All three isoforms of FGF-2 (24, 22, and 18 kDa) were significantly increased by MS. The MS-mediated increase of fgf-2 mRNA was caused by new synthesis and not stabilization. Pretreatment of MC3T3-E1 cells with cycloheximide showed that the induction of fgf-2 did not require new protein synthesis. Pretreating MC3T3-E1 cells with the mitogen-activated protein kinase (MAPK)/ERK kinase 1/2 (MEK1/2) inhibitor, U0126, or H-89, a PKA inhibitor, significantly inhibited the induction of fgf-2, showing that mechanical induction of fgf-2 is dependent on ERK and PKA signaling pathways. The downstream consequence of a single 15-minute stress pulse was a 3.5-fold increase in cell number in MC3T3-E1 compared with growth in nonstressed control cells. In studies using bone marrow osteoprogenitor cells (BMOp) isolated from Fgf2+/+and Fgf2−/− mice, we found that FGF-2 was necessary for a full proliferative response to MS.
Conclusions: These studies show that FGF-2 is an immediate-early gene induced by MS, and its expression is mediated by both the PKA and MAPK signal transduction pathways. FGF-2 was required for a full proliferative response.
Transgenic Mice Overexpressing Macrophage Migration Inhibitory Factor (MIF) Exhibit High-Turnover Osteoporosis
Authors: Onodera Shin , Sasaki Satoshi , Ohshima Shigeki , Amizuka Norio , Li Minqi , Udagawa Nobuyuki , Irie Kazuharu , Nishihira Jun , Koyama Yoshikazu , Shiraishi Ayako , Tohyama Harukazu , Yasuda Kazunori 
Published: June 2006

Abstract
The bone phenotype of mice overexpressing MIF was studied. These mice showed decreased trabecular bone, increased bone formation rate, and increased MMP-3, −9, and −13 mRNA expression in the femora and tibias. This model provides evidence of the role played by MIF in bone remodeling and balance in vivo.
Introduction: The role of macrophage migration inhibitory factor (MIF) in in vivo bone remodeling remains unelucidated. We describe disordered bone metabolism in transgenic mice overexpressing MIF.
Materials and Methods: For in vivo study, μCT, bone histomorphometry, blood and urine biochemical data, and gene expression of MIF transgenic (MIF Tg) mice and littermate wildtype (WT) mice were examined. For in vitro study, osteoclastogenesis in the co-culture of bone marrow cells and osteoblasts from MIF Tg and WT were assessed.
Results: μCT analyses revealed a significant reduction in the trabecular bone of distal femur in MIF Tg at 8–12 weeks of age. Histomorphometric analysis revealed increase in several measures of bone formation. Osteoclastogenesis was not influenced by the origin of bone marrow cells or osteoblasts. Urine level of deoxypyridinoline/creatinine and the mRNA levels of matrix metalloproteinase (MMP) −3, −9, and −13 in femurs were elevated in MIF Tg.
Conclusions: Overexpression of MIF causes high-turnover osteoporosis in mice. The increased expression of MMPs in bone was suggested, at least in part, as one cause of this phenotype, because MMPs plays important roles for bone resorption without affecting the formation of osteoclasts. This model provides evidence of the role played by MIF in bone remodeling and balance.
Teriparatide Increases Bone Formation in Modeling and Remodeling Osteons and Enhances IGF-II Immunoreactivity in Postmenopausal Women With Osteoporosis
Authors: Ma Yanfei L , Zeng Qingqiang , Donley David W , Ste-Marie Louis-Georges , Gallagher J Christopher , Dalsky Gail P , Marcus Robert , Eriksen Erik Fink 
Published: June 2006

Abstract
Transiliac bone biopsies were obtained from 55 women treated with teriparatide or placebo for 12–24 months. We report direct evidence that modeling bone formation at quiescent surfaces was present only in teriparatide-treated patients and bone formation at remodeling sites was higher with teriparatide than placebo.
Introduction: Recombinant teriparatide [human PTH(1-34)], a bone formation agent for the treatment of osteoporosis when given once daily subcutaneously, increases biochemical markers of bone turnover and activation frequency in histomorphometry studies.
Materials and Methods: We studied the mechanisms underlying this bone-forming action of teriparatide at the basic multicellular unit by the appearance of cement lines, a method used to directly classify surfaces as modeling or remodeling osteons, and by the immunolocalization of IGF-I and IGF-II. Transiliac bone biopsies were obtained from 55 postmenopausal women treated with teriparatide 20 or 40 μg or placebo for 12–24 months (median, 19.8 months) in the Fracture Prevention Trial.
Results: A dose-dependent relationship was observed in modeling and mixed remodeling/modeling trabecular hemiosteons. Trabecular and endosteal hemiosteon mean wall thicknesses were significantly higher in both teriparatide groups than in placebo. There was a dose-dependent relationship in IGF-II immunoreactive staining at all bone envelopes studied. The greater local IGF-II presence after treatment with teriparatide may play a key role in stimulating bone formation.
Conclusions: Direct evidence is presented that 12–24 months of teriparatide treatment induced modeling bone formation at quiescent surfaces and resulted in greater bone formation at remodeling sites, relative to placebo.
Function and Regulation of Osteopontin in Response to Mechanical Stress
Authors: Fujihara Shinji , Yokozeki Masahiko , Oba Yasuo , Higashibata Yuji , Nomura Shintaro , Moriyama Keiji 
Published: June 2006

Abstract
Extensive histological study revealed the impairment of bone remodeling caused by mechanical stress in OPN knockout mice in a tooth movement system. Analysis of OPN promoter transgenic mice showed the mechanical stress response element(s) in the 5.5-kb upstream region. These results were also obtained with the primary cultured cells.
Introduction: Mechanical loading system changes the bone architecture through the stimulation of bone remodeling by the action of a numbers of molecules. Among them, we showed that osteopontin (OPN) plays an important role in response to mechanical loading in rats with an experimental system for tooth movement. The results indicate the important role of OPN in bone remodeling. However, the molecular mechanism of OPN expression in response to mechanical stress is unknown.
Materials and Methods: OPN knockout mice and transgenic mice carrying green fluorescent protein (GFP) in the control of the OPN promoter were used for analysis. Orthodontic closed coil springs were bonded to the maxillary first molars and incisors for the experimental tooth movement. Spatial expression of GFP and OPN was detected by in situ hybridization.
Results: In contrast to wildtype mice, a smaller number of TRACP+ cells was detected in OPN knockout mice after treatment. In GFP-OPN5.5 mice, OPN and GFP mRNA-expressing cells were detected in bone cells after treatment, and the localization of GFP was consistent with that of endogenous OPN. An increase in the co-expression of GFP and OPN was detected when primary cultured osteoblastic cells derived from the transgenic mice were exposed to strain or pressure force. Significant increase in the number of OPN+ osteocyte was detected in the pressure side at 48 h after treatment. At 72 h, increase in the number of TRACP+ cells was detected predominantly in the pressure side.
Conclusions: Bone remodeling in response to mechanical stress was suppressed in OPN knockout mice. These results indicate the critical role of OPN in the process of bone remodeling. The analysis of GFP expression in the promoter transgenic mice indicated the presence of an in vivo mechanical stress response element in the 5.5-kb upstream region of the OPN gene.
A Nonself Recognition Gene Complex inNeurospora crassa
Authors: Micali Cristina O , Smith Myron L 
Published: June 2006

AbstractNonself recognition is exemplified in the fungal kingdom by the regulation of cell fusion events between genetically different individuals (heterokaryosis). The het-6 locus is one of ∼10 loci that control heterokaryon incompatibility during vegetative growth of N. crassa. Previously, it was found that het-6-associated incompatibility in Oak Ridge (OR) strains involves two contiguous genes, het-6 and un-24. The OR allele of either gene causes “strong” incompatibility (cell death) when transformed into Panama (PA)-background strains. Several remarkable features of the locus include the nature of these incompatibility genes (het-6 is a member of a repetitive gene family and un-24 also encodes the large subunit of ribonucleotide reductase) and the observation that un-24 and het-6 are in severe linkage disequilibrium. Here, we identify “weak” (slow, aberrant growth) incompatibility activities by un-24PA and het-6PA when transformed separately into OR strains, whereas together they exhibit an additive, strong effect. We synthesized strains with the new allelic combinations un-24PA het-6OR and un-24OR het-6PA, which are not found in nature. These strains grow normally and have distinct nonself recognition capabilities but may have reduced fitness. Comparing the Oak Ridge and Panama het-6 regions revealed a paracentric inversion, the architecture of which provides insights into the evolution of the un-24–het-6 gene complex.
ELM1 Is Required for Multidrug Resistance in Saccharomyces cerevisiae
Authors: Souid Abdul-Kader , Gao Chen , Wang Luming , Milgrom Elena , Shen W-C Winston 
Published: June 2006

Abstract
In Saccharomyces cerevisiae, transcription of several drug transporter genes, including the major transporter gene PDR5, has been shown to peak during mitosis. The significance of this observation, however, remains unclear. PDR1 encodes the primary transcription activator of multiple drug transporter genes in S. cerevisiae, including PDR5. Here, we show that in synchronized PDR1 and pdr1-3 (multidrug resistant) strains, cellular efflux of a known substrate of ATP-binding-cassette transporters, doxorubicin (a fluorescent anticancer drug), is highest during mitosis when PDR5 transcription peaks. A genetic screen performed to identify regulators of multidrug resistance revealed that a truncation mutation in ELM1 (elm1-300) suppressed the multidrug resistance of pdr1-3. ELM1 encodes a serine/threonine protein kinase required for proper regulation of multiple cellular kinases, including those involved in mitosis, cytokinesis, and cellular morphogenesis. elm1-300 as well as elm1Δ mutations in a pdr1-3 strain also caused elongated bud morphology (indicating a G2/M delay) and reduction of PDR5 transcription under induced and noninduced conditions. Interestingly, mutations in several genes functionally related to ELM1, including cla4Δ, gin4Δ, and cdc28-C127Y, also caused drastic reductions in drug resistance and PDR5 transcription. Collectively, these data show that ELM1, and genes encoding related serine/threonine protein kinases, are required for regulation of multidrug resistance involving, at least in part, control of PDR5 transcription.
Simultaneous Fine Mapping of Multiple Closely Linked Quantitative Trait Loci Using Combined Linkage Disequilibrium and Linkage With a General Pedigree
Authors: Lee S H , Van der Werf J H J 
Published: June 2006

Abstract
Within a small region (e.g., &lt;10 cM), there can be multiple quantitative trait loci (QTL) underlying phenotypes of a trait. Simultaneous fine mapping of closely linked QTL needs an efficient tool to remove confounded shade effects among QTL within such a small region. We propose a variance component method using combined linkage disequilibrium (LD) and linkage information and a reversible jump Markov chain Monte Carlo (MCMC) sampling for model selection. QTL identity-by-descent (IBD) coefficients between individuals are estimated by a hybrid MCMC combining the random walk and the meiosis Gibbs sampler. These coefficients are used in a mixed linear model and an empirical Bayesian procedure combines residual maximum likelihood (REML) to estimate QTL effects and a reversible jump MCMC that samples the number of QTL and the posterior QTL intensities across the tested region. Note that two MCMC processes are used, i.e., an (internal) MCMC for IBD estimation and an (external) MCMC for model selection. In a simulation study, the use of the multiple-QTL model clearly removes the shade effects between three closely linked QTL located at 1.125, 3.875, and 7.875 cM across the region of 10 cM, using 40 markers at 0.25-cM intervals. It is shown that the use of combined LD and linkage information gives much more useful information compared to using linkage information alone for both single- and multiple-QTL analyses. When using a lower marker density (11 markers at 1-cM intervals), the signal of the second QTL can disappear. Extreme values of past effective size (resulting in extreme levels of LD) decrease the mapping accuracy.
The F-Box Protein Dia2 Overcomes Replication Impedance to Promote Genome Stability in Saccharomyces cerevisiae
Authors: Blake Deborah , Luke Brian , Kanellis Pamela , Jorgensen Paul , Goh Theo , Penfold Sonya , Breitkreutz Bobby-Joe , Durocher Daniel , Peter Matthias , Tyers Mike 
Published: June 2006

Abstract
The maintenance of DNA replication fork stability under conditions of DNA damage and at natural replication pause sites is essential for genome stability. Here, we describe a novel role for the F-box protein Dia2 in promoting genome stability in the budding yeast Saccharomyces cerevisiae. Like most other F-box proteins, Dia2 forms a Skp1-Cdc53/Cullin-F-box (SCF) E3 ubiquitin–ligase complex. Systematic analysis of genetic interactions between dia2Δ and ∼4400 viable gene deletion mutants revealed synthetic lethal/synthetic sick interactions with a broad spectrum of DNA replication, recombination, checkpoint, and chromatin-remodeling pathways. dia2Δ strains exhibit constitutive activation of the checkpoint kinase Rad53 and elevated counts of endogenous DNA repair foci and are unable to overcome MMS-induced replicative stress. Notably, dia2Δ strains display a high rate of gross chromosomal rearrangements (GCRs) that involve the rDNA locus and an increase in extrachromosomal rDNA circle (ERC) formation, consistent with an observed enrichment of Dia2 in the nucleolus. These results suggest that Dia2 is essential for stable passage of replication forks through regions of damaged DNA and natural fragile regions, particularly the replication fork barrier (RFB) of rDNA repeat loci. We propose that the SCFDia2 ubiquitin ligase serves to modify or degrade protein substrates that would otherwise impede the replication fork in problematic regions of the genome.
Spatial and Temporal Divergence of Expression in Duplicated Barley Germin-Like Protein-Encoding Genes
Authors: Federico Maria L , Iñiguez-Luy Federico L , Skadsen Ronald W , Kaeppler Heidi F 
Published: June 2006

AbstractSubfunctionalization is the process by which a pair of duplicated genes, or paralogs, experiences a reduction of individual expression patterns or function while still reproducing the complete expression pattern and function of the ancestral gene. Two germin-like protein (GLP)-encoding genes, GerB and GerF, are paralogs that belong to a small gene family in barley (Hordeum vulgare). Both genes share high nucleotide sequence similarity in coding and noncoding regions and encode identical apoplastic proteins. The use of RNA gel blots, coupled with single-stranded conformation polymorphism (SSCP) analysis of RT–PCR products, elucidated the developmental and tissue-specific expression patterns of each gene. Individual expression patterns provided evidence of both overlapping redundancy and early subfunctionalization. GerB is predominantly expressed in developing shoots, while GerF is predominantly expressed in seedling roots, developing spikes, and pericarp/testa. GerF promoter deletion studies located a region (−356/−97) responsible for high promoter activity and showed the ability of GerB and GerF upstream regions to drive gfp expression in coleoptiles, epicarps, and lemma/palea of developing spikes. The observed expression patterns are consistent with proposed roles in plant development and defense mechanisms for this gene family. These roles may explain why redundancy has been selectively maintained in this duplicate gene pair.
Long-Term Evolution and Functional Diversification in the Members of the Nucleophosmin/Nucleoplasmin Family of Nuclear Chaperones
Authors: Eirín-López José M , Frehlick Lindsay J , Ausió Juan 
Published: June 2006

Abstract
The proper assembly of basic proteins with nucleic acids is a reaction that must be facilitated to prevent protein aggregation and formation of nonspecific nucleoprotein complexes. The proteins that mediate this orderly protein assembly are generally termed molecular (or nuclear) chaperones. The nucleophosmin/nucleoplasmin (NPM) family of molecular chaperones encompasses members ubiquitously expressed in many somatic tissues (NPM1 and -3) or specific to oocytes and eggs (NPM2). The study of this family of molecular chaperones has experienced a renewed interest in the past few years. However, there is a lack of information regarding the molecular evolution of these proteins. This work represents the first attempt to characterize the long-term evolution followed by the members of this family. Our analysis shows that there is extensive silent divergence at the nucleotide level suggesting that this family has been subject to strong purifying selection at the protein level. In contrast to NPM1 and NPM-like proteins in invertebrates, NPM2 and NPM3 have a polyphyletic origin. Furthermore, the presence of selection for high frequencies of acidic residues as well as the existence of higher levels of codon bias was detected at the C-terminal ends, which can be ascribed to the critical role played by these residues in constituting the acidic tracts and to the preferred codon usage for phosphorylatable amino acids at these regions.