21-09-2016, 04:04 PM
Hi am yamini i would like to get details on antisense rna technology and its applications ppt ..My friend said antisense rna technology and its applications ppt will be available here and i last studied in the college and now am doing MSc i need help
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In cases where a gene has been identified and assigned a particular phenotype, additional approaches are often required to exactly probe the function of gene.
Such hurdles in gene identification and manipulation can be overcome by antisense RNA technology.
Many genomic loci contain transcription units on both strands, therefore two oppositely oriented transcripts can overlap. While one strand codes for a protein, the transcript from the other strand is non-encoding. Such natural antisense transcripts (NATs) can negatively regulate the conjugated sense transcript.
NATs are highly prevalent in a wide range of species—for example, around 15% of human protein-encoding genes have an associated NAT. NATs can be divided into cis-NATs, which are transcribed from opposing DNA strands at the same genomic locus. trans-NATs are transcribed from separate loci. cis-NAT pairs display perfect sequence complementarity, whereas trans- NAT pairs display imperfect complementarity and can target many sense targets to form complex regulation network.
One ingenious and promising approach exploits the specificity of hybridization reactions between two complementary nucleic acid chains. Normally, only one of the two DNA strands in a given portion of double helix is transcribed into RNA and it is always the same strand for a given gene.
If a cloned gene is engineered so that the opposite DNA strand is transcribed instead, it will produce antisense RNA molecules that have a sequence complementary to the normal RNA transcripts. Antisense RNA, when synthesized in large enough amounts, will often hybridize with the “sense” RNA made by the normal genes and thereby inhibit the synthesis of the corresponding protein (Fig. 141).
A related method is to synthesize short antisense nucleic acid molecules by chemical or enzymatic means and then inject (or otherwise deliver) them into cells, again blocking (though only temporarily) production of the corresponding protein.