Nuclear Run-On

3 Promoter Deletion Analysis/Reporter Gene Assays 

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The methods used for the evaluation of regulation of gene expression are too numerous to be described in detail here. They include Northern analysis to determine levels of a particular mRNA, nuclear run on to determine whether an increase in mRNA is due to an increase in the rate of transcription, and promoter deletion analysis to identify specific elements in the promoter region responsible for the control of expression. Of much current interest is the use of microarrays that permit the study of the expression of hundreds to thousands of genes at the same time. Reverse transcriptase-polymerase chain reaction and RNase protection assay techniques are used to amplify and quantitate mRNAs, while the electrophoretic mobility shift assay is used to measure binding of a transcription factor to its specific DNA consensus sequence. 

Okamoto, T., Mitsuhashi, M., andKikkawa, Y. (1994) Fluorometric nuclear run-on assay with oligonucleotide probe immobilized on plastic plates. Anal. 

The soybean GH3 clone was initially isolated by differential hybridization screening as an auxin-induced cDNA clone from etiolated hypocotyls [9]. Nuclear run-on experiments have shown that transcription of the GH3 gene is induced within 5 minutes after auxin treatment of excised soybean plumules [20]. The soybean GH3 gene is specifically induced by biologically active auxins. Unlike SAURs and Aux/IAA mRNAs, GH3 mRNAs do not accumulate in response to protein synthesis inhibitors like cycloheximide... 

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