Amplification of DNA Probe Signals, DNA Probes, Protein Molecules, mRNA Molecules, Monoclonal Antibodies, Sigle Copy Gene

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Chimeric DNA Molecular Probes and Gene Libraries Chimeric DNA Molecular Probes and Gene Libraries Introduction Restriction Enzymes for Cloning Technique of Restriction Mapping Restriction Clevage and Gel Electrophoresis Construction of a Restriction Map Use of Partial Digests end Labelling and Hybridization in Restriction Mapping Construction of Chimeric DNA Cloning of Plasmid Vectors Directional Cloning of DNA Fragments with Heterologus Protruding Termini Adding Poly dA at 3' Ends of DNA Clone Blunt End Ligation by T4 DNA Ligase Cloning in Phage λ and Cosmid Vectors Cloning in phage λ Vectors Cloning in Cosmid Vectors Hosts for Cloning Vectors Bacteria as Hosts Eukaryotes as Hosts Molecular Probes Preparation of Probes Genomic DNA Probes

Home >> Biotechnology and Genomics >> Chimeric DNA Molecular Probes and Gene Libraries >> Amplification of DNA Probe Signals

Your Ad Here	Amplification of DNA probe signals During 1980s and early 1990s, DNA probe assays and immunoassays (using antibodies) competed with each other for a variety of purposes. While DNA probes have an advantage of detecting the presence of gene rather than its product, the immunoassay has the advantage of getting amplified target (the gene product) firstly due to transcription (several mRNA molecules can be synthesized on single copy of gene) and secondly due to translation (several protein molecules can be produced from same mRNA molecule).
The amplified target gives an amplified singal. Therefore, if DNA probes have to compete with monoclonal antibodies involving immunassay, DNA probe signals need to be amplified. Following devices have been used for signal amplification. (i) Probes have been developed for rRNA, since rRNA genes are present in thousands thus amplifying the target. (ii) Polymerase chain reaction (PCR) technology (which utilizes a thermostable polymerase) is used to generate rnil1ions of copies of target DNA sequence. which can then be identified by standard methods (for more details consult next chapter).
(iii) Signal generating capacity of the probe can also be increased by anyone of the following methods: (i) concentrating more label at the site of target molecule by attaching multiple enzyme molecules to each of its DNA probe or (ii) by using multiple probes or (iii) by attaching multiple enzymes to each of the multiple probes. (iv) Ampliprobe technology uses multiple secondary probes (each having one or more enzyme molecules) that hybridize to multiple target specific primary probes. The secondary probe is independent of target but helps in amplifying the signal. These approaches have been described as 'Christmas Tree' or 'Christmas Forest' approaches.The above amplification systems have played a significant role in the use of DNA probes for a variety of purposes.	Your Ad Here

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c DNA Probes Synthetic Oligonucleotides as Probes RNA Probes or Riboprobes Labelling of Probes Radiolablled Probes Non Radioactive Probes Biotin Labelled Probes Digoxigenin Labelled Probes Alternatives to Biotin and Digoxigenin Labelling Amplification of DNA Probe Signals Techniques Used in Molecular Probing Southern Nothern and Western Blotting Southern Blotting Northern Blotting Western Blotting Dot Blots and Slot Blots Applications of Molecular Probes Construction and Screening of Genomic and cDNA Libraries Genomic Library by Shotgun Experiment cDNA Library from mRNAs Colony or Plaque Hybridization for Screening of Libraries Chromosome Walking and Characterization of Chromosome Segments Chromosome Jumping or Hopping Libraries BAC Libraries and Assembly of BACs into Contigs

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