I am isolation RNA from Drosophila larvae brain with TRIzol method. What percentage of extracted RNA will be ribosomal RNA? I am only interested in mRNA, so I am trying to figure out whether I need to get rid of rRNA. Thanks
The protocol you are using will not only leave the sample with rRNA but also non coding RNA.
Many RNA protocols will separate mRNA by affinity of a carrier to the polyA tail. This protocol references an older paper that estimates that only 5% of RNA is mRNA. I'd be surprised if this ratio changed by more than 2-3 fold in drosophila.
I assume that %age is by weight but it could be a densitometry measurement which is similarly interpreted.