Dual origin of tissue-specific progenitor cells in Drosophila tracheal remodeling

During Drosophila metamorphosis, most larval cells die. Pupal and adult tissues form from imaginal cells, tissue-specific progenitors allocated in embryogenesis that remain quiescent during embryonic and larval life. Clonal analysis and fate mapping of single, identified cells show that tracheal system remodeling at metamorphosis involves a classical imaginal cell population and a population of differentiated, functional larval tracheal cells that reenter the cell cycle and regain developmental potency. In late larvae, both populations are activated and proliferate, spread over and replace old branches, and diversify into various stalk and coiled tracheolar cells under control of fibroblast growth factor signaling. Thus, Drosophila pupal/adult tissue progenitors can arise both by early allocation of multipotent cells and late return of differentiated cells to a multipotent state, even within a single tissue.     

Human recombinant granulocyte-macrophage colony-stimulating factor: a multilineage hematopoietin

Human recombinant granulocyte-macrophage colony-stimulating factor (GM-CSF) was tested for its ability to induce colony formation in human bone marrow that had been enriched for progenitor cells. In addition to its expected granulocyte-monocyte colony-stimulating activity, the recombinant GM-CSF had burst-promoting activity for erythroid burst-forming units and also stimulated colonies derived from multipotent (mixed) progenitors. In contrast, recombinant erythroid-potentiating activity did not stimulate erythroid progenitors. The experiments prove that human GM-CSF has multilineage colony-stimulating activity.     

"Pure" human hematopoietic progenitors: permissive action of basic fibroblast growth factor

Methodology has been developed that enables virtually complete purification and abundant recovery of early hematopoietic progenitors from normal human adult peripheral blood. A fraction of the pure progenitors is multipotent (generates mixed colonies) and exhibits self-renewal capacity (gives rise to blast cell colonies). This methodology provides a fundamental tool for basic and clinical studies on hematopoiesis. Optimal in vitro cloning of virtually pure progenitors requires not only the stimulatory effect of interleukin-3, granulocyte-macrophage colony-stimulating factor, and erythropoietin, but also the permissive action of basic fibroblast growth factor. These findings suggest a regulatory role for this growth factor in early hematopoiesis.     

生长分化因子9在兔卵巢中的免疫组织化学定位

［目的］探讨生长分化因子9（GDF9）在兔卵巢卵泡发生过程中的调控机制。［方法］采用免疫组织化学方法测定GDF9蛋白在兔卵巢中的表达定位情况。［结果］GDF9在原始卵泡中没有表达;在初级卵泡、次级卵泡和有腔卵泡卵母细胞及有腔卵泡颗粒细胞、透明带及卵泡液中均检测到GDF9蛋白;在黄体中也有GDF9的表达。［结论］GDF9不仅是卵母细胞分泌因子,而且是颗粒细胞的分泌因子,其表达随兔卵巢中卵泡发生呈时空动态变化,在兔卵巢卵泡发生过程中发挥了重要作用,参与了黄体活动的调节。     

A bifunctional bacterial protein links GDI displacement to Rab1 activation

Rab guanosine triphosphatases (GTPases) regulate vesicle trafficking in eukaryotic cells by reversibly associating with lipid membranes. Inactive Rab GTPases are maintained in the cytosol by binding to GDP-dissociation inhibitor (GDI). It is believed that specialized proteins are required to displace GDI from Rab GTPases before Rab activation by guanosine diphosphate-guanosine 5'-triphosphate (GDP-GTP) exchange factors (GEFs). Here, we found that SidM from Legionella pneumophila could act as both GEF and GDI-displacement factor (GDF) for Rab1. Rab1 released from GDI was inserted into liposomal membranes and was used as a substrate for SidM-mediated nucleotide exchange. During host cell infection, recruitment of Rab1 to Legionella-containing vacuoles depended on the GDF activity of SidM. Thus, GDF and GEF activity can be promoted by a single protein, and GDF activity can coordinate Rab1 recruitment from the GDI-bound pool.     

Isolation of single human hematopoietic stem cells capable of long-term multilineage engraftment

Lifelong blood cell production is dependent on rare hematopoietic stem cells (HSCs) to perpetually replenish mature cells via a series of lineage-restricted intermediates. Investigating the molecular state of HSCs is contingent on the ability to purify HSCs away from transiently engrafting cells. We demonstrated that human HSCs remain infrequent, using current purification strategies based on Thy1 (CD90) expression. By tracking the expression of several adhesion molecules in HSC-enriched subsets, we revealed CD49f as a specific HSC marker. Single CD49f(+) cells were highly efficient in generating long-term multilineage grafts, and the loss of CD49f expression identified transiently engrafting multipotent progenitors (MPPs). The demarcation of human HSCs and MPPs will enable the investigation of the molecular determinants of HSCs, with a goal of developing stem cell-based therapeutics.     

山羊生长分化因子9基因外显子2 的PCR-SSCP分析

【目的】寻找与产羔数相关的遗传标记，为山羊高繁殖力的标记辅助选择提供科学依据。【方法】以控制Belclare绵羊和Cambridge绵羊高繁殖力的生长分化因子9（growth differentiation factor 9, GDF9）基因为候选基因，根据绵羊GDF9基因序列设计4对引物，采用PCR-SSCP技术检测GDF9基因外显子2在高繁殖力山羊品种(济宁青山羊)以及低繁殖力山羊品种(波尔山羊、文登奶山羊、辽宁绒山羊、北京本地山羊)中的单核苷酸多态性，同时研究该基因对济宁青山羊高繁殖力的影响。【结果】山羊与绵羊的GDF9基因外显子2核苷酸序列同源性为99%(955/965)。引物1和引物4存在多态性。对于引物1扩增片段，5个山羊品种均检测到AA、AB和BB 3种基因型，测序分析发现外显子2第26 bp处有1个G→A的单碱基突变，但没有引起氨基酸改变；济宁青山羊A等位基因频率为0.9128，B等位基因频率为0.0872；AA基因型济宁青山羊产羔数最小二乘均值比AB基因型的多0.54只(P<0.01)，比BB基因型的多0.63只(P<0.01)。对于引物4扩增片段，5个山羊品种均检测到CC、CD和DD 3种基因型，测序分析发现外显子2第792 bp处有1个G→A的单碱基突变并且导致缬氨酸改变为异亮氨酸；济宁青山羊C等位基因频率为0.9266，D等位基因频率为0.0734；CC基因型济宁青山羊产羔数最小二乘均值比CD基因型的多0.57只(P<0.01)，比DD基因型的多0.62只(P<0.01)。【结论】初步表明GDF9基因可能是控制济宁青山羊多胎性能的一个主效基因或是与之存在紧密遗传连锁的分子标记。     

AREG对绵羊卵丘细胞葡萄糖代谢的影响

为研究双调蛋白（AREG）对绵羊卵丘细胞（Cumulus cells,CCs）葡萄糖代谢的影响,采集来源于中腔卵泡和小腔卵泡的卵丘-卵母细胞复合体（COCs）,利用荧光定量PCR检测中、小腔卵泡卵丘细胞葡萄糖代谢相关基因表达;添加AREG进行卵丘细胞的体外培养和卵母细胞的体外成熟（IVM）,检测卵丘细胞的增殖,测定培养液或细胞中的葡萄糖、乳酸、NADPH和ATP含量。结果表明：1）来源于小腔卵泡的卵丘细胞G6PDH、PFKL和PFKM的mRNA表达量以及细胞增殖能力显著低于中腔卵泡卵丘细胞（P<0.05）;2）较低浓度（10ng/mL）的AREG显著提高了中腔卵泡卵丘细胞的增殖能力（P<0.05）而对小腔卵泡卵丘细胞无影响（P>0.05）,在生长分化因子9(GDF9)和骨形态发生蛋白15(BMP15)的协同作用下,10ng/mL AREG可以显著提高两者的增殖能力（P<0.05）且两者间差异不显著（P>0.05）;3）在GDF9和BMP15的协同作用下,AREG可显著提高不同直径腔卵泡卵丘细胞培养液中的葡萄糖消耗、乳酸生成、NADPH生成以及细胞中的ATP...     

绵羊高繁殖力候选基因GDF9的多态性分析

为寻找与绵羊产羔数相关的分子遗传标记,根据生长分化因子9(GDF9)基因序列设计引物,采用PCR-SSCP技术检测GDF9基因突变位点的多态性,研究不同基因型和小尾寒羊产羔数间的相关性.检测结果表明:小尾寒羊、白萨福克和特克赛尔绵羊都检测出AA、AB和BB 3种基因型,而在藏羊中只检测到AA、AB 2种基因型.测序结果表明,BB型为突变纯合型,其外显子2的75个碱基发生了C→T的突变(G2突变),没有引起氨基酸的改变,为沉默突变.小尾寒羊产羔数的最小二乘均值关系为AB>AA>BB,但3种基因型间差异不显著(P>0.05).GDF9基因的G2突变对小尾寒羊高繁殖力没有显著影响.     

Microinjected c-myc as a competence factor

While a number of oncogenes are expressed in a cell cycle-dependent manner, their role in the control of cell proliferation can only be established by a direct functional assay. The c-myc protein, upon microinjection into nuclei of quiescent Swiss 3T3 cells, cooperated with platelet-poor plasma in the stimulation of cellular DNA synthesis. This suggests that c-myc protein, like platelet-derived growth factor (PDGF), may act as a competence factor in the cell cycle to promote the progression of cells to S phase. The presence in the medium of an antibody against PDGF abolished DNA synthesis induced by microinjected PDGF; however, the microinjected c-myc protein stimulated DNA synthesis even when its own antibody was present in the medium. The c-myc protein may act as an intracellular competence factor, while PDGF expresses its biological activity only from outside the cells.     

安徽白山羊、波尔山羊GDF9和BMP15基因的RFLP分析

以绵羊高繁殖性能主效基因,生长分化因子9(growth differentiation factor 9,GDF9)和骨形态发生蛋白15(bone morphogenetic protein 15,BMP15)基因为候选基因,采用PCR-RFLP方法检测其在安徽白山羊、波尔山羊中的多态性。结果表明,均未能检测至GDF9基因的G8突变(C→T)及BMP15基因的B4突变(G→T)。这2个山羊群体中均为野生型,由此表明这2个候选基因检测位点在安徽白山羊、波尔山羊中没有多态性。     

cDNA Cloning of Goat DNA Methyltransferase 1,Screening of shRNA Vectors and Influences to Development of Nuclear Transfer Embryos

This study was designed to clone cDNA of goat DNA methyltransferase 1（DNMT1） gene,to screen an effective shRNAproducing vector targeting goat DNA methyltransferase 1 and to improve the developmental competence of goat nuclear transfer embryos by decreasing the DNMT1 expression in donor cells.In this study,PCR primers were designed against regions of high homology between bovine and sheep sequences and then used to amplify the larger portions of the coding regions.Next,3 RNAi oligonucleotides were designed based on the cloned sequences and inserted into pRNAT-U6.1/Neo vector,acquiring 3 new vectors,respectively termed pRNAD1,pRNAD2 and pRNAD3.Then the positive cells were sorted by flow cytometry after transfection and detected by real-time PCR analysis and sodium bisulfite genomic sequencing.Finally,the developmental rates of nuclear transfer（NT） embryos generated using donor cells with and without the effective shRNA vector respectively,as well as in vitro fertilization（IVF） embryos were observed and recorded.The results showed that the coding regions of goat DNA methyltransferase 1 gene was successfully cloned（GenBank no.FJ617538）.Furthermore,an effective interfering shRNA（pRNAD2） was obtained,with its interference effect being 47.88%.Finally,NT embryos with shRNA vector harbored better developmental competence during morula and blastocyst stage compared to controls（P 〈 0.05）,reaching the similar rates to IVF embryos（P 〉 0.05）.In conclusion,goat DNA methyltransferase 1 gene cDNA was cloned and sequenced,an effective shRNA vector responsible for inhibiting DNA methyltransferase 1 expression was developed and the developmental competence of goat nuclear transfer morulae and blastcysts was significantly improved,which provided a feasible pathway for improving goat nuclear transfer embryo development competence by decreasing the methylation level in donor cells through RNAi-mediated manner.     

宁夏滩羊·小尾寒羊及滩寒杂交群体BMP15基因和GDF9基因多态性研究

[目的]研究宁夏滩羊、小尾寒羊及杂交群体的骨形态发生蛋白15（BMP15）和生长分化因子9（GDF9）基因多态性,为宁夏滩羊的保种及育种工作提供科学依据。[方法]以宁夏滩羊、小尾寒羊及滩寒杂交群体为研究对象,分别设计2对引物,采用PCR-RFLP方法和PCR-SSCP检测方法,检测BMP15基因和GDF9基因在宁夏滩羊、小尾寒羊及滩寒杂交群体中的多态性。[结果]BMP15基因的2对引物扩增结果的RFLP分析表明,不存在多态性位点;GDF9基因的2对引物扩增片段的SSCP分析结果表明,只有引物1扩增片段存在多态性位点,但未发现碱基序列发生改变。[结论]GDF9基因可能是控制小尾寒羊多胎性能的1个主效基因或是与之存在紧密遗传连锁的分子标记。     

羊多胎性状候选基因的研究进展

从骨形态发生蛋白15(BMP15)基因、生长分化因子9(GDF9)基因、视黄醇结合蛋白4(RBP4)基因、视黄酸受体γ(RARG)基因、催乳素(PRL)基因、催乳素受体(PRLR)基因、褪黑激素受体基因、促性腺激素释放激素(GnRH)及其受体(GnRHR)基因方面综述了羊多胎性状候选基因的研究进展.     

绵羊GDF9基因FecTT突变检测

FecTT是冰岛Thoka绵羊GDF9基因外显子2编码区1279位发生的A→C突变(A1279C),导致编码GDF9蛋白C末端成熟肽第109位丝氨酸改变为精氨酸(S109R),该突变纯合子母羊不育,杂合子母羊产羔数比野生型多0.6只。本研究采用PCR-RFLP方法分析了GDF9基因FecTT突变在小尾寒羊、洼地绵羊、湖羊、考力代、白萨福克、黑萨福克、东弗里生、杜泊绵羊、特克塞尔、多赛特和中国美利奴11个绵羊品种中的分布。结果表明在11个绵羊品种中都没有检测到GDF9基因的FecTT突变,提示GDF9基因影响Thoka绵羊高繁殖力的FecTT突变对以上11个绵羊品种的繁殖力均没有显著影响。