File Name: of animal viruses and gene cloning.zip
Vector (molecular biology)
Not a MyNAP member yet? Register for a free account to start saving and receiving special member only perks. These procedures take advantage of the absence of Not I and Asc I restriction enzyme sites within the viral genome and use reporter genes for the identification of recombinant viruses. Genes for secreted engineered alkaline phosphatase and green fluorescent protein were placed under simian virus 40 early promoter control and flanked by Not I and Asc I restriction sites. When permissive cells were cotransfected with herpesvirus saimiri virion DNA and one of the engineered reporter genes cloned within herpesvirus saimiri sequences, recombinant viruses were readily identified and purified on the basis of expression of the reporter gene. Replacement of the reporter gene can be achieved by Not I or Asc I digestion of virion DNA and ligation with a terminally matched fragment or, alternatively, by homologous recombination in cotransfected cells. These procedures should be widely applicable in their general form to most or all herpesviruses that replicate permissively in cultured cells.
Recombinant DNA Research and Viruses
Cloning is the process of producing individuals with identical or virtually identical DNA , either naturally or artificially. In nature, many organisms produce clones through asexual reproduction. Cloning in biotechnology refers to the process of creating clones of organisms or copies of cells or DNA fragments molecular cloning. The term clone , coined by Herbert J. In botany, the term lusus was traditionally used. Cloning is a natural form of reproduction that has allowed life forms to spread for hundreds of millions of years. It is the reproduction method used by plants, fungi, and bacteria, and is also the way that clonal colonies reproduce themselves.
Metrics details. Viruses of the genus Begomovirus Geminiviridae are emerging economically important plant viruses with a circular, single-stranded DNA genome. However, the phenotypic effects of naturally occurring mutations have never been extensively investigated in geminiviruses, particularly because, to be infectious, cloned viral genomes usually require sub-cloning as complete or partial tandem repeats into a binary vector from Agrobacterium tumefaciens. Using Tomato yellow leaf curl virus TYLCV , we show here that infectivity can be obtained when only a nucleotide region containing a highly conserved stem-loop is repeated. A binary vector containing this nt region and a unique restriction site was created, allowing direct cloning of infectious monomeric viral genomes provided that they harbour the same restriction site at the corresponding nucleotide position.
The term cloning describes a number of different processes that can be used to produce genetically identical copies of a biological entity. The copied material, which has the same genetic makeup as the original, is referred to as a clone. Researchers have cloned a wide range of biological materials, including genes, cells, tissues and even entire organisms, such as a sheep. In nature, some plants and single-celled organisms, such as bacteria , produce genetically identical offspring through a process called asexual reproduction. In asexual reproduction, a new individual is generated from a copy of a single cell from the parent organism. Natural clones, also known as identical twins, occur in humans and other mammals.
The genome of SV40 contains very little non-essential DNA so it is necessary to insert the foreign gene in place of essential viral genes and to propagate the.
GENETICS OF ANIMAL VIRUSES
Vaccines may contain either living or killed organisms or purified antigens from these organisms. Vaccines containing living organisms tend to trigger the best protective responses. Killed organisms or purified antigens may be less immunogenic than living ones because they are unable to grow and spread in the host.
The papers in the compendium focus on the basic genetic model systems; the uses of genetic approaches to study basic problems in molecular biology; and on the increasing application of genetic systems to the study of more complex viral-host interactions such as viral virulence and persistence. Microbiologists, cellular biologists, and virologists will find the book insightful. Contributors Preface I. We are always looking for ways to improve customer experience on Elsevier.
Reverse genetics systems have been established for all major groups of plant DNA and positive-strand RNA viruses, and our understanding of their infection cycles and pathogenesis has benefitted enormously from use of these approaches. However, technical difficulties have heretofore hampered applications of reverse genetics to plant negative-strand RNA NSR viruses. The procedure involves Agrobacterium -mediated transcription of full-length SYNV antigenomic RNA and co-expression of the nucleoprotein N , phosphoprotein P , large polymerase core proteins and viral suppressors of RNA silencing in Nicotiana benthamiana plants. Deletion analyses also showed that the glycoprotein is not required for systemic infection, although the glycoprotein mutant was defective in virion morphogenesis.
The four major types of vectors are plasmids , viral vectors , cosmids , and artificial chromosomes.