A nuclear run-ON assay is conducted to identify the genes that are being transcribed at a CERTAIN TIME. This method allows changes in TRANSCRIPTION RATES to be measured, which often differ from steady-state mRNA levels used in microarrays.

Nuclear run-OFFassay:

A method to determine which genes in a population of cells are expressed at a GIVEN TIME. NASCENT RNA transcripts are radiolabelled with [32P]NTPs as they are elongated in isolated nuclei (new transcripts are not initiated in these isolated nuclei). To determine if a specific gene is expressed, the radiolabelled run-off transcripts are used as hybridization probes with DNA from recombinant plasmids that contain the gene of interest (GoI).

But when i have gone through the both method it seems to be similar.The methods are same in both the cases.Can u kindly clarify what is basic difference between these methods.thank you

Yes that's right, the expression is similar, but when you use nuclear run-ON assay, you can measure the mRNA level: up or down regulated directly at the certain time. but not by nuclear run-OFF assay cause use a partial gene....

Dear Fatchivah

Thanks for your topic.

I want to know: what is different between run on/off assay & microarray assay