The biological function of type I receptors of bone morphogenetic protein in bone

Bone morphogenetic proteins （BMPs） have multiple roles in skeletal development, homeostasis and regeneration. BMPs signal via type I and type II serine/threonine kinase receptors （BMPRI and BMPRII）. In recent decades, genetic studies in humans and mice have demonstrated that perturbations in BMP signaling via BMPRI resulted in various diseases in bone, cartilage, and muscles. In this review, we focus on all three types of BMPRI, which consist of activin-like kinase 2 （ALK2, also called type IA activin receptor）, activin- llke kinase 3 （ALK3, also called BMPRIA）, and activin-like kinase 6 （ALK6, also called BMPRIB）. The research areas covered include the current progress regarding the roles of these receptors during myogenesis, chondrogenesis, and osteogenesis. Understanding the physiological and pathological functions of these receptors at the cellular and molecular levels will advance drug development and tissue regeneration for treating musculoskeletal diseases and bone defects in the future.

Influence of bone morphogenetic protein type IA receptor conditional knockout in lens on expression of bone morphogenetic protein 4 in lens

AIM: To investigate the influence of bone morphogenetic protein type IA receptor [BMPR-IA(ALK3)] conditional knockout in lens on expression of bone morphogenetic protein 4(BMP4) in lens during the development of the vertebrate eye.METHODS: Cre-positive mice were mated with Crenegative mice to generate 50% Cre-positive(conditional knockout, CKO) 4 embryos, 8 eyes and 50% Cre-negative offspring(wild type, WT) 4 embryos, 8 eyes. The embryos were fixed in 4% paraformaldehyde, embedded in paraffin, and sectioned to a thickness of 4 μm.Removal of paraffin wax and dehydrating for sections,and then the procedure of in situ hybridization was processed, BMP4 MK1784-m(BOSTER) was used, and observed the expression of BMP4 in the lens in experimental group and control group. We selected SPSS11.0 software for statistical analysis, P【0.05 showed that the difference was statistically significant.· RESULTS: Four embryos of each genotype were examined, totally we had 8 embryos, 16 eyes. We got the uniform outcomes in all the embryos. We found ALK3 was required during lens growing, but was not essential for the formation of lens. We observed that the expression of BMP4 in the lens was significantly reduced in all 8 ALK3 CKO lens, BMP4 expression was normal in all the 8 WT lens, P 【0.01. This phenomenon became increasingly visible in accordance with embryo development. The most apparent alteration was present at stage E15.5.CONCLUSION: ALK3 is essential for lens growth. The influence of ALK3 on the expression of BMP4 is present during the development of mice lens.

Bone Morphogenetic Protein 15 as a Candidate Gene for Prolificacy of Jining Grey Goat

On the basis of the ovine bone morphogenetic protein 15(BMP15)gene,two pairs of primers(PI and P2)were designed to amplify exons 1 and 2 of the BMP15 gene in five randomly selected does of both Angora and Jining Grey goats.The sequences of BMP15 exon 1(P1 amplification)of Angora and Jining Grey goats were identical.There was a 3-nucleotide(CTT)insertion in positions 268 to 270 of goat BMP 15 exon1 compared with that of sheep(GenBank accession number AF236078),which caused a leucine insertion in the 12th position of amino acid sequence.Sequence length of goat BMP 15 exon 2(P2 amplification)was identical with that of sheep(AF236079),but there were seven nucleotide and four amino acid changes between goat and sheep.The nucleotide in the 963rd position of BMP15 exon 2 was A for Angora goat and sheep,and G for Jining Grey goat.Based on this A963G mutation,primer pair P3 was designed to detect single nucleotide polymorphism of BMP15 exon 2 in breeds of high prolificacy(Jining Grey),moderate prolificacy(Boer)and low prolificacy(Angora and Inner Mongolia Cashmere)by polymerase chain reactionsingle strand conformation polymorphism(PCR-SSCP).Three genotypes(AA,AG and GG)were detected in Jining Grey goats,two genotypes(AG and GG)in Boer,and only the AA genotype in Angora and Inner Mongolia Cashmere goats.Sequencing revealed one mutation(A963G)in genotype GG compared with genotype AA,and this mutation resulted in an amino acid change of serine→glycine(S300G).In Jining Grey goats,frequencies of AA,AG and GG genotypes were 0.008,0.059 and 0.933,respectively.Genotypic distributions of the BMP 15 gene were significantly different(P<0.05 or P<0.001)between Jining Grey and Boer,Angora,and Inner Mongolia Cashmere goats.In Jining Grey goats,the does with the GG genotype had 0.71(P<0.05)or 1.57(P<0.05)additional kids than did those with AG or AA genotypes,and does with the AG genotype had 0.86(P<0.05)more kids than did those with the AA genotype.These results tentatively indicate that the BMP15 gene is either a major gene that affects prolificacy in Jining Grey goats,or may be a molecular marker in close linkage with such a gene.

Expression of Vascular Endothelial Growth Factor in Bone Morphogenetic Protein-2 Induced Osteogenesis

An experimental model of femoral muscular pouch in 20 mice was adopted. The expression of VEGF was examined by in situ hybridization method and immunohistochemical method in bone morphogenetic protein- 2 induced osteogenesis . The experimental results demonstrated that the expression signals of VEGF mRNA and VEGF appeared in cytoplasm during condensation of mesenehymal cell. As the mesenchymal cells differentiated into precartilage, the expression signals decreased in mesenehymal cells, but increased in chondrocytes and kept getting denser in the process of cartilage maturity. The peak expression of VEGF mRNA and VEGF in the experimental group appeared on the 14 th day, accompanied by numerons hypertrophic chondrocytes. When mature cartilage calcified and neu, bone trabecula formed, the expression of VEGF mRNA and VEGF decreased in chondrocytes, but still expressed moderately in the osteoblasts and osteocytes. Signals of VEGF mRNA and VEGF can not be detected in the control groups.

Roles and regulation of bone morphogenetic protein-7 in kidney development and diseases

The gene encoding bone morphogenetic protein-7(BMP7) is expressed in the developing kidney in embryos and also in the mature organ in adults. During kidney development, expression of BMP7 is essential to determine the final number of nephrons in and proper size of the organ. The secreted BMP7 acts on the nephron progenitor cells to exert its dual functions: To maintain and expand the progenitor population and to provide them with competence to respond to differentiation cues, each relying on distinct signaling pathways. Intriguingly, in the adult organ, BMP7 has been implicated in protection against and regeneration from injury. Exogenous administration of recombinant BMP7 to animal models of kidney diseases has shown promising effects in counteracting inflammation, apoptosis and fibrosis evoked upon injury. Although the expression pattern of BMP7 has been well described, the mechanisms by which it is regulated have remained elusive and the processes by which the secretion sites of BMP7 impinge upon its functions in kidney development and diseases have not yet been assessed. Understanding the regulatory mechanisms will pave the way towards gaining better insight into the roles of BMP7, and to achieving desired control of the gene expression as a therapeutic strategy for kidney diseases.

Construction of Adeno-associated Virus System for Human Bone Morphogenetic Protein 7 Gene

To construct the recombinant adeno-associated virus （rAAV） vector with human bone morphogenetic protein 7 （BMP7） and observe the BMP7 mRNA expression in vitro, BMP7 CDS sequence was cloned into expression plasmid pAAV-MCS of AAV Helper Free System. The recombinant plasmid was identified with enzyme digestion and sequencing. The recombinant plasmid, pAAV-RC, pHelper were co-transfected into AAV-293 cells according to the calcium phosphate-based protocol. The viral stock was collected by 4 rounds of freeze/thaw. After purified and concentrated, the recombinant virus titer was determined by dot-blot assay. HEK293 cells were transfected with the recombinant virus at different MOI, and the expression of BMP7 mRNA was detected by RT-PCR. The results showed rAAV-BMP7 was constructed and packaged successfully. The physical particle titer was 2.5×10^11 vector genomes/mL. There was different expression level of BMP7 mRNA after transfecton. These data suggested that recombinant AAV mediated a stable expression of hBMP7 mRNA in 293 cells. The AAV production method may pave the way of an effective strategy for the jaw bone defection around dental implants.

Establishment and identification of fibroblast clones expressing human bone morphogenetic protein 2

Objective:To establish fibroblasts stably expressing human bone morphogenetic protein 2(hBMP2). Methods:Eukaryonic expression vector(pcDNA3.1-B2) was transduced into NIH3T3 cells using SofastTM, a new generation cationic polymer gene transfection reagent. The positive cell clones were selected with G418. The stable transfection and expression of BMP2 in the NIH3T3 cells were determined by RT-PCR and immunohistochemical stain. Results: BMP2 mRNA was transcripted and expressed in the transfected NIH3T3 cells. Conclusion: With positive compound transfection, outside human BMP2 gene can be successfully transducted into NIH3T3 cells, which is the key step to induce periodontal cells to osseous phenotypes.

Cloning, expression profiling and promoter functional analysis of bone morphogenetic protein 2 in the tongue sole(Cynoglossus semilaevis)

BMP2 plays crucial roles in vertebrate developmental process and acts as a bone inducer during osteogenesis. We present here the molecular cloning of bmp2 cDNA from the marine flatfish Cynoglossus semilaevis, and the analysis of bmp2 expression profiling and promoter function. The full length of bmp2 cDNA sequence is 2 048 bp,which encodes a protein of 422 amino acids. Tissue expression distribution of bmp2 was examined in 14 tissues of mature individuals by quantitative real time PCR（qRT-PCR）. The results revealed that bmp2 was expressed ubiquitously, and the highest expression level was detected in the spinal cord. Moreover, bmp2 expression levels were detected at 15 sampling time points of early developmental stages（egg, larva, juvenile and fingerling stages）.The highest expression level of bmp2 was observed at the gastrula stage, which was about ten times higher than those at the other three embryo stages. Whole-mount in situ hybridization showed that the bmp2 signal was strongly detected at the location of the crown-like larval fin, heart and liver, and slightly expressed in the notochord at one day post hatch（dph）; then the expression of bmp2 started to be concentrated in notochord at three dph. Subsequently, we characterized the 5′-flanking region of bmp2 by testing the promoter activity by Luciferase reporter assays. Positive regulatory region was detected at the location of –179 to ＋109. The predicted transcription factor binding sites（E-box binding factors, zinc finger transcription factor, etc.） in this region might participate in the transcriptional regulation of the bmp2 gene.

Molecular Cloning and Sequence Analysis of FullLength cDNA Encoding Human Bone Morphogenetic Protein—7

Objective:To clone the full-length human bane morphogenetic protein-7 (BMP-7 ) gene and analyse its sequence, to aid in investigation of its function and structure. Methods : Total RNA was isolated from Chinese fetal kidney by the acid gmnidinium thiocyanate phenol-chloroform method. Two overlapping segments of human BMP- 1 cDNA were obtained by reverse transcription (RT)-PCR. Following application, the two segments were ligated to each other and subcloned into POEM-T easy vector to form PEGM-T easy/hBMP-7 recombinant plasmid. Sanger dideoxy chain-termination method was used to sequence the cDNA. Results. There was 750 bp fragment obtained RT-PCR using #2 primer from 5' end of BMP-7 gene (PCR by using # 2 and # 1) ,and 540 bp fragment from 3' end was generated by KT-PCR using # 4 primer (PCR using # 3 and # 4). Full-length cDNA encoding BMP-7 was obtained by religation of two segments. When compared with hBMP-7 sequence in Gene bank (XM30619) ,our full-length BMP-7 cDNA has a G instead of a T at nucleotide 862. This change results in valine substituting for phenylalanine in the protein. Conclusion. This is the first time that BMP-7 cDNA was successfully cloned from Chinese fetal kidney. BMP-7 cDNA plays an important role in healing injuries of the osteo-articular system. This makes BMP-7 is an attractive target far various clinical applications.

Construction of bicistronic green fluorescent protein labeled pSELECT GFPzeo human bone morphogenetic protein 2 eukaryotic expression vector

Objective To construct green fluorescent protein (GFP)-labeled pSELECT-GFP zeohBMP2 eukaryotic expression vector.Methods The encoding fragment of hBMP2 gene was obtained from a recombinant plasmid pcDNA3.1/CT-hBMP2 by using polymerase

Expression of mature peptide of human bone morphogenetic protein-2 in Escherichia coli

To express die mature peptide of human bone morphogenetic protein-2 in Escherichia coil. Methods: TheDNA fragment encoding the mature peptide of human bone morphogenetic protein-2 (hBMP-2m) was inserted into expression vectorpDH in which foreign gene was controlled by PRPL promoters. E. coli DH5a transformed with recombinant plasmid pDHB2m wasinduced at 42℃to express the target protein. The expressed product was partially purified and refolded, and then implanted intorat thigh muscles to assay its bone inductive activity. Results: After induction, a protein band on SDS-PAGE gel with an apparentmol. wt. of 13kD was observed to anticipate in the strain carrying pDHB2m, but not in the control. The expressed hBMP-2m accounted for 45%-60% of the total bacterial protein. The expressed product existed in a form of inclusion body. After partially purified and refolded, rhBMP-2m could induce the formation of cartilage and bone tissue heterotopically. Conclusion: The maturepeptide of human bone morphogenetic protein-2 has ben successfully expressed in E. coli and the product has ectopic bone inductive activity.

CO-TRANSFECTION OF RAT BONE MARROW MESENCHYMAL STEM CELLS WITH HUMAN BMP2 AND VEGF165 GENES

Objective To explore the feasibility and efficacy of lentivirus-mediated co-transfection of rat bone marrow mesenchymal stem cells (MSCs) with human vascular endothelial growth factor 165 (hVEGF165) gene and human bone morphogenetic protein 2 (hBMP2) gene. Methods The hVEGF165 and hBMP2 cDNAs were obtained from human osteosarcoma cell line MG63 and cloned into lentiviral expression vectors designed to co-express the copepod green fluorescent protein (copGFP). The expression lentivector and packaging Plasmid Mix were co-transferred to 293TN cells, which produced the lentivirus carrying hVEGF165 (Lv-VEGF) or hBMP2 (Lv-BMP), respectively. MSCs of Wistar rats were co-transfected with Lv-BMP and Lv-VEGF (BMP+VEGF group), or each alone (BMP group and VEGF group), or with no virus (Control group). The mRNA and protein expressions of hVEGF165 and hBMP2 genes in each group were detected by real-time PCR and enzyme linked immunosorbent assay (ELISA). Results Lentiviral expression vectors carrying hVEGF165 or hBMP2 were correctly constructed and confirmed by restriction endonucleses analysis and DNA sequencing analysis. A transfer efficiency up to 90% was archieved in all the transfected groups detected by the fraction of fluorescent cells using fluorescent microscopy. From the results generated by real-time PCR and ELISA, VEGF165 and BMP2 genes were co-expressed in BMP+VEGF group. No significant difference of BMP2 expression was detected between BMP+VEGF and BMP groups (P>0.05). Similarly, there was no significant difference of VEGF165 expression between BMP+VEGF and VEGF groups (P>0.05). Conclusion VEGF165 and BMP2 genes were successfully co-expressed in MSCs by lentivirus-mediated co-transfection, which provided a further foundation for the combined gene therapy of bone regeneration.

GDF-9和BMP-15在PCOS卵泡发育及胰岛素抵抗中的研究进展

生长分化因子-9(growth differentiation factor-9,GDF-9)和骨形态生成蛋白-15(bone morphogenetic protein-15,BMP-15)是转化生长因子-β(transforming growth factor-β,TGF-β)超家族的组成部分,在卵巢中参与颗粒细胞和卵母细胞的增殖分化,影响卵母细胞的发育和质量,调节卵巢功能。GDF-9和BMP-15异常表达,影响卵泡发育和透明带结构,可能是导致多囊卵巢综合征(polycystic ovary syndrome,PCOS)患者不孕的重要环节。BMP-15激活Smad1/5/8信号通路,可能还与PCOS患者的胰岛素抵抗密切相关。但是,血清中GDF-9和BMP-15蛋白难以精确定量,血清GDF-9和BMP-15水平难以作为PCOS特异性诊断与治疗评估的标志。综述GDF-9和BMP-15在卵泡发育中的作用、PCOS患者卵巢GDF-9和BMP-15异常表达对卵泡发育及胰岛素抵抗的影响,探讨GDF-9和BMP-15在PCOS诊治中的潜在应用价值。

小尾寒羊高繁殖力候选基因BMP15和GDF9的研究

以控制Belclare和Cambridge绵羊高繁殖力的骨形态发生蛋白 15 (bonemorphogeneticprotein 15 ,BMP15 )基因和生长分化因子 9(growthdifferentiationfactor 9,GDF9)基因为候选基因 ,采用PCR RFLP技术检测BMP15基因和GDF9基因在高繁殖力绵羊品种 (小尾寒羊、湖羊 )以及低繁殖力绵羊品种 (多赛特羊、特克塞尔羊、德国肉用美利奴羊 )中的单核苷酸多态性 ,同时研究这两个基因对小尾寒羊高繁殖力的影响。结果表明 :在 5个绵羊品种中都没有检测到GDF9基因的G8突变 (C→T) ,也没有检测到BMP15基因的B4突变 (G→T)。高繁殖力的小尾寒羊在BMP15基因编码序列第 718位碱基处发生了与Belclare绵羊和Cambridge绵羊相同的B2突变 (C→T) ,而其余 4个绵羊品种则没有发生这种突变。对于BMP15基因的B2突变 ,在小尾寒羊中检测到AA、AB两种基因型 ,A等位基因频率为 0 734,B等位基因频率为 0 2 6 6。小尾寒羊与其余 4个绵羊品种间B2突变基因型分布差异极显著 (P <0 0 0 1)。突变杂合基因型 (AB)小尾寒羊平均产羔数比野生纯合基因型 (AA)多 0 6 2只 (P <0 0 1)。研究结果表明 ,BMP15B2突变对小尾寒羊高繁殖力影响作用十分明显 。

6个山羊品种高繁殖力候选基因BMP15多态性研究

骨形态发生蛋白15(bone morphogenetic prote in 15,BMP15)基因为控制Belc lare和Cambridge绵羊高繁殖力的主效基因。采用PCR-RFLP和PCR-SSCP技术检测BMP15基因中与绵羊高繁殖力相关的两个突变位点在高繁殖力山羊品种济宁青山羊(130只母羊、20只公羊)以及低繁殖力山羊品种(波尔山羊30只母羊、文登奶山羊30只母羊、辽宁绒山羊30只母羊、内蒙古绒山羊50只母羊、北京本地山羊30只母羊)中的单核苷酸多态性,同时研究这两个突变位点对济宁青山羊高繁殖力的影响。结果表明,在6个山羊品种中都没有检测到BMP15的B2突变(C→T);检测到的BMP15的B4突变(G→T)在6个山羊品种中均呈现杂合子状态。这表明BMP15基因中影响Belc lare和Cambridge绵羊高繁殖力的突变位点对济宁青山羊的高繁殖力没有显著影响。

小尾寒羊和湖羊高繁殖力候选基因BMP15的研究

以控制RomneyInverdale绵羊和RomneyHanna绵羊高繁殖力的骨形态发生蛋白15(bonemorphoge-neticprotein15,BMP15)基因为候选基因,采用PCR-RFLP方法检测BMP15基因在高繁殖力绵羊品种(小尾寒羊、湖羊)以及低繁殖力绵羊品种(道赛特羊、萨福克羊)中的多态性,同时研究该基因对小尾寒羊高繁殖力的影响。结果表明,BMP15基因在小尾寒羊、湖羊、道赛特和萨福克绵羊中既没有发生与Inverdale绵羊相同的V31D突变,也没有发生与Hanna绵羊相同的Q23Ter突变。还表明BMP15基因中影响Inverdale绵羊和Hanna绵羊高繁殖力的突变位点对小尾寒羊和湖羊的高繁殖力没有显著影响。

牛GDF9和BMP15基因遗传变异与双胎性状的关系研究

以生长分化因子9（Growth differentiation factor 9,GDF9）基因和骨形态发生蛋白15（Bone morphogenetic protein 15,BMP15）基因作为牛双胎性状的候选基因,研究了它们在鲁西牛、秦川牛、南阳牛和中国荷斯坦牛4个品种中的遗传变异,并在鲁西牛群体中研究了其多态位点与双胎性状的关系.结果表明：在鲁西牛中GDF9基因的3＇UTR发现缺失突变,而其它3个品种中没有发现该突变.对鲁西牛群体中该多态位点与单、双胎性状之间进行卡方显著性检验表明,单胎牛群体与双胎牛群体基因型分布有极显著的差异（P=0.006）,双胎牛群体的B等位基因频率明显大于单胎牛群体.通过生物信息学分析表明,突变体mRNA的二级结构与野生型相比总自由能值差异不大,但突变体mRNA翻译起始位点的二级结构稳定性明显大于野生型.在鲁西牛、南阳牛和秦川牛的BMP15基因中发现编码区第759～762 位有GAAA 4个碱基存在缺失突变,但没有检测到突变纯合个体,中国荷斯坦牛中没有检测到该突变.卡方显著性检验表明单胎牛群体和双胎牛群体在该位点基因型组成差异不显著（P=0.947）.

绵羊骨形态发生蛋白受体-1B基因研究进展

绵羊繁殖性能在绵羊产业中有着重要意义,除通过一些技术手段(如同期发情、人工授精、超数排卵等)之外,在目前已知的关于能够提高绵羊繁殖力的16个基因共20个突变体当中,以骨形态发生蛋白受体-1B(bone morphogenetic protein receptor type-1B,BMPR-1B)基因对绵羊繁殖力的影响最大。BMPR-1B基因是世界上第一个被发现的多羔主效基因,其编码区的A746G突变导致蛋白质序列中第249位的谷氨酰胺被置换为精氨酸(Q249R),最终能够引起绵羊排卵数和产羔数增加。作者介绍了绵羊多羔主效基因BMPR-1B及其突变体FecB(A746G)的发现与结构,简述了该基因分子方面的作用机理,对BMP/Smad信号通路的调控以及与绵羊繁殖之间的联系,并简单分析了FecB突变后对绵羊卵巢、卵泡等组织细胞功能,激素调节和相关基因表达的影响。进一步加深对BMPR-1B基因的了解,为研究人员探明该基因诱使绵羊等动物提高产羔数的调控机制,相关配体、调控因子和上下游信号蛋白的影响以及加快哺乳动物高效育种繁殖、扩大种群规模和多胎品系的建立,增加养殖人员的经济收入等提供一些参考和帮助。

山羊高繁殖力候选基因BM P15的RFLP分析

以控制R om ney Inverdale绵羊和R om ney H anna绵羊高繁殖力的骨形态发生蛋白15(BM P 15)基因为候选基因,采用PCR-RFLP方法检测BM P 15基因在高繁殖力山羊品种(济宁青山羊)以及低繁殖力山羊品种(内蒙古绒山羊、安哥拉山羊、波尔山羊)中的多态性,同时研究该基因对济宁青山羊高繁殖力的影响。结果表明:BM P 15基因在济宁青山羊、内蒙古绒山羊、安哥拉山羊和波尔山羊中既未发生与Inverdale绵羊相同的V 31D突变,也未发生与H anna绵羊相同的Q 23T er突变。这表明BM P 15基因这2个突变位点对济宁青山羊的高繁殖力没有显著影响。