Abstract:

Discovery of regulatory RNA molecules during last years has played an important role in controlling gene expression and has led todevelopment of a new research area. About 21 nucleotide long, short RNA molecules were first discovered in plants. By now, it is wellknown that small RNA molecules inhibit mRNA transformation in cytoplasm and break mRNA molecules to regulate gene expression.Many different functionally small RNAs that play an important role in regulating genome structure and function are waiting to beexplored. The silencing of gene expression by RNAi pathways, are processed through the "small interfering RNA (siRNA)" and microRNA (miRNA) which are small, negative regulators of gene expression and non protein-coding RNA fragments.

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