Genome-wide prediction of C. elegans genetic interactions

To obtain a global view of functional interactions among genes in a metazoan genome, we computationally integrated interactome data, gene expression data, phenotype data, and functional annotation data from three model organisms-Saccharomyces cerevisiae, Caenorhabditis elegans, and Drosophila melanogaster-and predicted genome-wide genetic interactions in C. elegans. The resulting genetic interaction network (consisting of 18,183 interactions) provides a framework for system-level understanding of gene functions. We experimentally tested the predicted interactions for two human disease-related genes and identified 14 new modifiers.     

High-resolution epitope mapping of hGH-receptor interactions by alanine-scanning mutagenesis

A strategy, called alanine-scanning mutagenesis, was used to identify specific side chains in human growth hormone (hGH) that strongly modulate binding to the hGH receptor cloned from human liver. Single alanine mutations (62 in total) were introduced at every residue contained within the three discontinuous segments of hGH (residues 2 to 19, 54 to 74, and 167 to 191) that have been implicated in receptor recognition. The alanine scan revealed a cluster of a dozen large side chains that when mutated to alanine each showed more than a four times lower binding affinity to the hGH receptor. Many of these residues that promote binding to the hGH receptor are altered in homologs of hGH (such as placental lactogens and prolactins) that do not bind tightly to the hGH receptor. The overall folding of these mutant proteins was indistinguishable from that of the wild-type hGH, as determined by strong cross-reactivities with seven different conformationally sensitive monoclonal antibodies. The alanine scan also identified at least one side chain, Glu174, that hindered binding because when it was mutated to alanine the receptor affinity increased by more than a factor of four.     

Genome-wide association and linkage mapping strategies reveal genetic loci and candidate genes of phosphorus utilization in soybean

Insufficient available phosphorus in soil has become an important limiting factor for the improvement of yield and quality in soybean. The mining of QTLs and candidate genes controlling soybean phosphorus utilization related traits is a necessary strategy to solve this problem. In this study, 11 phosphorus utilization related traits of a natural population of 281 typical soybean germplasms and a recombinant inbred line(RIL) population of 270 lines were evaluated under different phosphorus condit...     

B lineage--specific interactions of an immunoglobulin enhancer with cellular factors in vivo

The mouse heavy chain immunoglobulin gene contains a tissue-specific enhancer. The enhancer and flanking sequences were studied in vivo by carrying out dimethyl sulfate protection experiments on living cells, in combination with genomic sequencing. Relative to reactions on naked DNA, there are changes (protections and enhancements) in the reactivity of guanine residues to dimethyl sulfate within the enhancer sequence in myeloma, B, and early B cells, whereas virtually no alterations appear in cells of non-B lineage. Most of the affected residues are in four clusters, in sequences homologous to the octamer 5'CAGGTGGC 3' (C, cytosine; A, adenine; G. guanine; T, thymine). The alterations in the pattern of G reactivity are consistent with the tissue-specific binding of molecules to the mouse immunoglobulin heavy chain enhancer.     

Structure and flexibility adaptation in nonspecific and specific protein-DNA complexes

Interaction of regulatory DNA binding proteins with their target sites is usually preceded by binding to nonspecific DNA. This speeds up the search for the target site by several orders of magnitude. We report the solution structure and dynamics of the complex of a dimeric lac repressor DNA binding domain with nonspecific DNA. The same set of residues can switch roles from a purely electrostatic interaction with the DNA backbone in the nonspecific complex to a highly specific binding mode with the base pairs of the cognate operator sequence. The protein-DNA interface of the nonspecific complex is flexible on biologically relevant time scales that may assist in the rapid and efficient finding of the target site.     

Protein-DNA interactions in vivo upstream of a cell cycle-regulated human H4 histone gene

Cell cycle-dependent histone genes are transcribed at a basal level throughout the cell cycle, with a three- to fivefold increase during early S phase. Protein-DNA interactions in the 5' promoter region of a cell cycle-regulated human H4 histone gene have been analyzed at single-nucleotide resolution in vivo. This region contains two sites, with four potential protein-binding domains, at which the DNA is protected from reaction with dimethyl sulfate in cells and from digestion with deoxyribonuclease I in nuclei. These protein-DNA interactions persist during all phases of the cell cycle and dissociate with 0.16 to 0.2M sodium chloride.     

鸡全基因组选择信号筛选研究进展

人工选择对家鸡驯化及品种形成具有重要作用,基因组上留有选择痕迹。随着基因组技术和选择信号检测方法完善,在基因组上检测选择信号成为进化生物学领域研究热点。文章主要描述选择信号定义,总结检测选择信号的重要统计方法,分析鸡基因组选择信号检测结果,以期为鸡全基因组领域研究提供参考。     

玉米全基因组谷胱苷肽-S-转移酶基因家族的分析

谷胱苷肽转移酶(glutathione-S-transferase,GST)是植物生长发育过程中一类多功能酶,在植物的初级代谢和次级代谢以及调控植物的逆境胁迫和细胞信号转导等过程中具有重要作用。根据GST蛋白序列构建的隐马尔可夫模型(hidden markov model,HMM),鉴定玉米全基因组GST基因,并对GST基因数量、类型、染色体定位和进化关系进行分析。结果表明,玉米全基因组中共含有37个GST基因,在10条染色体上呈非随机分布,具有U型、F型和Z型3个亚族。与水稻比较,玉米未发现T亚族。该研究结果对深入了解GST基因家族的分子进化以及GST基因的克隆和功能验证提供了重要参考依据。     

玉米全基因组谷胱苷肽-S-转移酶基因家族的分析

谷胱苷肽转移酶(glutathione-S-transferase,GST)是植物生长发育过程中一类多功能酶,在植物的初级代谢和次级代谢以及调控植物的逆境胁迫和细胞信号转导等过程中具有重要作用。根据GST蛋白序列构建的隐马尔可夫模型(hidden markov model,HMM),鉴定玉米全基因组GST基因,并对GST基因数量、类型、染色体定位和进化关系进行分析。结果表明,玉米全基因组中共含有37个GST基因,在10条染色体上呈非随机分布,具有U型、F型和Z型3个亚族。与水稻比较,玉米未发现T亚族。该研究结果对深入了解GST基因家族的分子进化以及GST基因的克隆和功能验证提供了重要参考依据。     

杜洛克猪全基因组连锁不平衡分析

利用猪Illumina Porcine SNP60K芯片对福建某核心种猪场杜洛克猪216个个体进行基因型检测,基于该高密度SNP芯片数据,运用Haploview软件计算全基因组连锁不平衡并构建杜洛克猪连锁不平衡图谱。结果表明,该杜洛克猪群体不同染色体上相邻标记间r2存在波动,波动范围为0.46~0.59,相邻标记间的平均连锁不平衡程度r2为0.52,SSC10的r2最低(平均为0.46),SSC6的r2最高(平均为0.59),连锁不平衡水平随着标记间距的增加而衰减、变异程度随之减小。该研究结果可为杜洛克猪遗传分析及全基因组选择研究提供参考。     

Genome-wide Analysis of Ovate Family Proteins in Arabidopsis

Arabidopsis thaliana ovate family proteins (AtOFPs) is a newly found plant-specific protein family interacting with TALE (3-aa loop extension homeodomain proteins) homeodomain proteins in Arabidopsis. ...     

基于全基因关联分析的代谢组学在植物中的应用

植物代谢物是人类食物和营养物质的重要来源.代谢组学是对生物体内代谢物进行定量和定性分析,研究代谢物合成和调控机制的一门新兴学科.基于代谢组的全基因组关联分析(metabolome-based genome-wide association study,mGWAS)是将代谢组数据作为表型,与基因型数据进行关联分析的一种方...     

大豆抗倒伏相关性状全基因组关联分析

研究以150份大豆种质为试验材料开展2年3点试验,在收获期测定抗倒伏相关性状,并利用RTM-GWAS方法作关联分析,共检测到99个显著关联SNP位点,其中48个效应显著位点,解释0.28％～3.38％表型变异;89个与环境互作显著位点,解释0.53％～7.04％表型变异;其中,21个位点主效表型变异解释率高于1％;与6...     

Genome-wide insertional mutagenesis of Arabidopsis thaliana

Over 225,000 independent Agrobacterium transferred DNA (T-DNA) insertion events in the genome of the reference plant Arabidopsis thaliana have been created that represent near saturation of the gene space. The precise locations were determined for more than 88,000 T-DNA insertions, which resulted in the identification of mutations in more than 21,700 of the approximately 29,454 predicted Arabidopsis genes. Genome-wide analysis of the distribution of integration events revealed the existence of a large integration site bias at both the chromosome and gene levels. Insertion mutations were identified in genes that are regulated in response to the plant hormone ethylene.     

杧果RAV基因家族的全基因组分析

为了揭示RAV家族基因在杧果中的序列特征及其表达特性,采用生物信息学方法对杧果RAV家族基因进行序列分析,并通过qRT-PCR技术研究杧果胶孢炭疽菌和细菌性黑斑病菌侵染过程中该家族基因的相对表达量.结果表明,从杧果基因组中鉴定出6个RAV基因家族成员,其编码的蛋白质均具有AP2和B3超家族保守域结构,命名为MiRAV1...     

葡萄bHLH转录因子家族全基因组分析

通过生物信息学的方法,鉴定得到110个葡萄的bHLH基因,分别命名为VvbHLH001^VvbHLH110。葡萄bHLH基因可以分为24个亚家族,以非随机的方式分布在19条染色体上,其中有10组基因发生了串联复制。基因芯片表达分析显示葡萄bHLH基因具有器官特异性表达,如亚家族Ib(2)在根中特异表达,可能与根活力有关;VvbHLH003和VvbHLH16基因在花蕊及花序中特异表达,推测与花器官发育有关。研究结果可为进一步开展bHLH家族的基因功能和分子进化机制的研究提供基础。     

Genome-wide Identification and Analysis of DNA Methyltransferases in Grape

DNA methylation is an important epigenetic regulation mechanism, which is catalyzed by DNA methyltransferases. In this study, eight DNA methyltransferase genes were identified in grape genome to analyze the selective pressure, gene expression and codon usage bias. The results showed grape DNA methyltransferase MET subfamily underwent relatively strong purifying selection during evolution, while chromomethylase CMT subfamily underwent positive selection during evolution. Under different abiotic(heat, drought or cold) stresses, the expression level of many grape DNA methyltransferase genes changed significantly. The expression level of these genes might be related with cis-regulatory elements of their promoters. The results of codon usage bias analysis showed that synonymous codon bias existed in grape DNA methyltransferase gene family, which might be affected by mutation pressure. These results laid a solid foundation for in-depth study of DNA methyltransferases in grape.     

植物数量性状全基因组选择研究进展

全基因组选择是新近开始在植物数量性状研究和植物育种中应用的一种分析方法.它以连锁不平衡为基础,利用BLUP(best linear unbiased prediction)分析方法准确估计某一群体每一遗传标记的育种值,从而只利用这些预测的育种值来进行选择.文章综述了全基因组选择的原理、方法以及全基因组选择在植物育种方面的研究进展,探讨各种因素对全基因组选择的影响,并讨论了全基因组选择在植物数量性状分子育种研究中可能的应用.     

番茄Pto抗病基因家族的鉴定

由丁香假单胞杆菌番茄致病变种[Pseudomonas syringae pv.tomato(Okabe)Young,Dye&Wilikie](简称Pst)引起的细菌性斑点病是番茄生产上一种重要病害[1]。自1933年报道以来,已在美国、意大利、南非、澳大利亚等二十多个国家和地区发生[2]。在中国吉林省长春市的番茄大棚内首次发