Quantifying mRNA level

Question

[Natasha]

Hello,

How do we quantify the mRNA level of a gene present in a tissue? I am looking for the absolute mRNA levels of certain genes present in the skeletal tissue. Any help would be highly appreciated

Answer 1

[Kristoffer Vitting-Seerup]

If you work with human data I would recomend the GTEx protal where you can se the gene expression across most tissues

Answer 2

[Hussain Ather]

A very general question. Could you be more specific? Microarrays can be used in which, generally, mRNA from a tissue/cell line is used in creating samples that converted to a large number of DNA sequences that are immobilized onto a solid surface in an ordered array. (source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC444812/)

[Natasha]

I am trying to get a measure of the level of enzymes, catalyzing a set of reactions in the glycolysis pathway ,from the mRNA levels.The authors of this paper have discussed microarray provides relative levels, whereas RNAseq analysis gives absolute gene expression levels (with relevance to yeast). I would like to know if one can obtain the absolute levels for the genes present in human tissue.If yes,where can we look up for this information?

[GenoMax]

RNA-Seq provides expression levels in terms of counts of expressed transcripts that can be related to transcripts per cell and thus an absolute level.

The paper you linked has this quote. It is true that you get a count value with RNAseq but I doubt that is an absolute measurement. It is a digital measurement as opposed to microarrays where you have to convert an analog (Intensity) measurement to a digital value.

Note: I suspect the word absolute is being used as an adjective, meaning not relative or comparative.

[Natasha]

Thanks a lot for the response.By absolute I meant not comparitive/not a ratio .(for example,a diseased state vs control/normal )

Answer 3

[GenoMax]

You can look up gene expression values for normal human tissues via Illumina body map expression atlas page. Click on the organism parts link in left column. You can then select just skeletal muscle tissue in the dialog box that opens.

[Natasha]

Thanks a lot for providing the link.I am also looking for the expression levels in pancreatic tissue.I couldn't find the classification in the above mentioned page.Could you please help?