Structure and Expression of a-Amylase Gene from Vigna mungo

A single copy of the a-amylase gene, composed of three intronsand four exons, was found in Vigna mungo. Examination of levelsof a-amylase and its mRNA in detached cotyledons indicated thatattachment of the embryonic axis is not required for expressionof the gene in cotyledons of germinating seeds. (Received December 21, 1993; Accepted March 14, 1994)     

Characterization of the Fatty Acid Desaturase Genes in Cucumber: Structure,Phylogeny, and Expression Patterns

Fatty acid desaturases (FADs) introduce double bonds into the hydrocarbon chains of fatty acids to produce unsaturated fatty acids, and therefore play a critical role in plant development and acclimation to environmental stresses. In this study, 23 full-length FAD genes in cucumber (Cucumis sativus L.) were identified through database searches, including three CsFAB2 genes, two CsFAD2 genes, fourteen CsFAD5 genes, and one gene each for CsFAD3, CsFAD4, CsFAD6 and CsFAD7. These cucumber FAD genes were distributed on all seven chromosomes and two additional scaffolds. Based on a phylogenetic analysis, the cucumber FAD proteins were clustered into five subfamilies with their counterparts from other plants. Gene structures and protein sequences were considerably conserved in each subfamily. All three CsFAB2 proteins shared conserved structure with the known plant soluble FAD proteins. The other cucumber FADs belonged to the membrane-bound FADs and contained three highly conserved histidine boxes. Additionally, the putative endoplasmic reticulum retention signal was found at the C-termini of the CsFAD2 and CsFAD3 proteins, while the N-termini of CsFAD4, CsFAD5, CsFAD6, CsFAD7 and three CsFAB2s contained a predicted chloroplast signal peptide, which was consistent with their associated metabolic pathways. Furthermore, a gene expression analysis showed that CsFAD2 and CsFAD3 were universally expressed in all tested tissues, whereas the other cucumber FAD genes were preferentially expressed in the cotyledons or leaves. The tissue-specific expression patterns of cucumber FAD genes were correlated well with the differences in the fatty acid compositions ofroots and leaves. Finally, the cucumber FAD genes showed a cold-induced and heat-repressed expression pattern, although with distinct regulatory time courses among the different CsFAD members, which indicates the potential roles of the FADs in temperature stress resistance in cucumber.     

The Structure and Expression of Amylase Genes in Mammals: an Overview

Abstract

Austria is a small European country with a small number of universities and biotechnological industries, but with great efforts in the implementation of environmental consciousness and corresponding legal standards. This review attempts to describe the biotechnological landscape of Austria, thereby focusing on the highlights in research by industry, universities, and research laboratories, as published during 1990 to early 1995. These will include microbial metabolite (organic acids, antibiotics) and biopolymer (polyhydroxibutyrate, S-layers) production; enzyme (cellulases, hemicellulases, ligninases) technology and biocatalysis; environmental biotechnology; plant breeding and plant protection; mammalian cell products; fermenter design; and bioprocess engineering.     

The Context Organization of Functional Regions in Yeast Genes with High-Level Expression

With the example of yeast genes, context organization was compared for functional gene regions (promoter, 5"-UTR, 3"-UTR) and tested for association with the level of gene expression. Several parameters (nucleotide composition, dinucleotide content bias) proved to correlate with expression level, each functional region having its specific features. Context optimization of a functional region was assumed to be essential for highly efficient interaction with the expression system of the cell. Specific context features were considered as dispersed signals important for high-level gene expression.     

Chloroplast Genome of Vigna aconififolia and Localization of Certain Photosynthesis-related Genes

The restriction analysis of chloroplast genome of Vigna aeonitifolia has revealed that it is about 150 kb in size, similar to V. radiata. The restriction pattern of chloroplast DNA (cpDNA) for Pst I is also the same from both the species, but restriction fragment length polymorphism is observed in cases of Kpn I and Sstl. These differences in the restriction patterns have arisen because of the occurrence of different restriction sites in the chloroplast genome of V. aconitifolia. A restriction map of cpDNA for V. aeonitifolia has been prepared on the basis of these observations. Furthermore, seven genes (psbA, psbB, psbC, psbD, psaA, psaB and rbcL) — coding for polypeptides of photosystems I and II as well as the large subunit of ribulose 1,5-bisphosphate carboxylaseloxygenase — have been localized on the Pst I — and Kpn I — generated restriction fragments of V. aconitifolia with the help of heterologous gene-specific probes and their relative position on the restriction map is presented. The gene organization supports the view that an inversion of about 50 kb has occurred in Vigna cpDNA as compared to other species.     

Ontogeny of Somatic Embryos of Vigna aconitifolia, Vigna mungo and Vigna radiata

Callus cultures were initiated from immature cotyledons of Vignaaconitifolia, V. mungo and V. radiata on MS medium supplementedwith NAA, picloram or 2, 4-D. On transfer to L-6 liquid mediumsupplemented with low concentrations of picloram, GA₃ and cytokinins,large number of somatic embryos differentiated from the callus.The cells destined to become somatic embryos divided to formspherical or filamentous proembryos. From the filamentous proembryo,the embryo proper developed either at single or multiple sites.Development of somatic embryos from multiple sites resultedin several embryos connected by a common suspensor at the radicleend. Continued divisions of the proembryos led to globular,heart shaped and dicotyledonary stages of somatic embryogenesis.The somatic embryos of V. mungo and V. aconitifolia differentiatedinto tiny plantlets at low frequency (1%) in liquid suspensioncultures supplemented with zeatin, picloram and GA₃. Vigna aconitifolia Jacq, Marechal, mothbean, Vigna mungo L. Hepper, urdbean, Vigna radiata L. Wilczk, mungbean, somatic embryo     

Features of the Structure and Expression of NPM and NCL Genes in Cutaneous Melanoma

Molecular Biology - Malignant cutaneous melanoma (CM) is an extremely aggressive cancer characterized by a high level of metastatic activity and unfavorable prognosis due to a high incidence of...     

超抗原融合基因VEGF-SEA的克隆、原核表达及蛋白纯化

根据Genebank报道的VEGF(NM-003376)、SEA(A28664)基因序列,对密码子进行优化,合成血管内皮细胞生长因子和超抗原基因序列,将VEGF-SEA基因片段插入质粒pET22b构建重组质粒pET22b-VEGF-SEA.重组质粒经序列分析正确,转化大肠杆菌BL21(DE3)进行IPTG诱导表达,表达产物经SDS-PAGE分析蛋白条带与预期一致,证明融合蛋白原核表达成功.产物经His·Bind Buffer kit试剂盒纯化,纯度达到90%,这一成果为进一步研究VEGF-SEA融合蛋白的活性及其功能,探讨超抗原抑制肿瘤生长作用奠定了基础.     

Comparative Genomic Analysis of N2-Fixing and Non-N2-Fixing Paenibacillus spp.: Organization,Evolution and Expression of the Nitrogen Fixation Genes

We provide here a comparative genome analysis of 31 strains within the genus Paenibacillus including 11 new genomic sequences of N₂-fixing strains. The heterogeneity of the 31 genomes (15 N₂-fixing and 16 non-N₂-fixing Paenibacillus strains) was reflected in the large size of the shell genome, which makes up approximately 65.2% of the genes in pan genome. Large numbers of transposable elements might be related to the heterogeneity. We discovered that a minimal and compact nif cluster comprising nine genes nifB, nifH, nifD, nifK, nifE, nifN, nifX, hesA and nifV encoding Mo-nitrogenase is conserved in the 15 N₂-fixing strains. The nif cluster is under control of a σ⁷⁰-depedent promoter and possesses a GlnR/TnrA-binding site in the promoter. Suf system encoding [Fe–S] cluster is highly conserved in N₂-fixing and non-N₂-fixing strains. Furthermore, we demonstrate that the nif cluster enabled Escherichia coli JM109 to fix nitrogen. Phylogeny of the concatenated NifHDK sequences indicates that Paenibacillus and Frankia are sister groups. Phylogeny of the concatenated 275 single-copy core genes suggests that the ancestral Paenibacillus did not fix nitrogen. The N₂-fixing Paenibacillus strains were generated by acquiring the nif cluster via horizontal gene transfer (HGT) from a source related to Frankia. During the history of evolution, the nif cluster was lost, producing some non-N₂-fixing strains, and vnf encoding V-nitrogenase or anf encoding Fe-nitrogenase was acquired, causing further diversification of some strains. In addition, some N₂-fixing strains have additional nif and nif-like genes which may result from gene duplications. The evolution of nitrogen fixation in Paenibacillus involves a mix of gain, loss, HGT and duplication of nif/anf/vnf genes. This study not only reveals the organization and distribution of nitrogen fixation genes in Paenibacillus, but also provides insight into the complex evolutionary history of nitrogen fixation.     

Inheritance and Organization of Glycinin Genes in Soybean

Five genes (Gy1, through Gy5) encode most of the subunits that are assembled into glycinin, a predominant seed storage protein found in soybeans. Restriction fragment length polymorphisms are described that identify four of these five genes (Gy1/Gy2, Gy3, and Gy5). The fifth gene (Gy4) is characterized by two alleles, one of which (gy4) causes absence of the subunit. Genetic segregation studies indicate that the five genes are located at four genetic loci within the genome. Gy1 and Gy2 are in a direct tandem repeat at one locus, whereas there is a single glycinin gene at each of the other three loci. All four loci segregate independently from one another, and they also segregate independently from the genetic markers for tawny/grey pubescence (T/t), purple/white flower color (W1/w1), light/dark hilum pigmentation (l/ll), black/brown seed coat (R/r), and brown/tan pod color (I1I1L2L2/I1I1I2I2). The latter genetic markers are located on linkage groups 1 (t), 8 (w1), 7 (i), and 2 (r) in the soybean genome, respectively.     

Human Mucin Genes Assigned to 11p15.5: Identification and Organization of a Cluster of Genes

Four distinct genes that encode mucins have previously been mapped to chromosome 11p15.5. Three of these genes (MUC2, MUC5AC,andMUC6) show a high level of genetically determined polymorphism and were analyzed in the CEPH families. Linkage analysis placed all three genes on the genetic map in a cluster betweenHRASandINS,and more detailed analysis of recombinant breakpoints revealed thatMUC6is telomeric toMUC2.Using these recombinantsD11S150was mapped close toMUC2.Ten of the 11 recombinant chromosomes studied in detail were paternal, and the recombinant events were distributed throughout the 11p15 region, suggesting that the high level of recombination observed in 11p15.5 is not due to a particular recombinational hot spot. Pulsed-field gel electrophoresis was used to make a detailed physical map of theMUCcluster and to integrate the physical and genetical maps. The gene order was determined to beHRAS–MUC6–MUC2–MUC5AC–MUC5B–IGF2.TheMUCgenes span a region of some 400 kb and the map extends 770 kb and contains 15 putative CpG islands. The order of theMUCgenes on the map corresponds to the relative order of their expression along the anterior–posterior axis of the body, suggesting a possible functional significance to the gene order.