I am looking for a promoter that is expressed early (ideally starting from the 50 cell stage). I’d be grateful for some suggestions. I was also curious about rps-27. Is there any data out there regarding when the expression starts?
his-72 is one candidate. The Murray lab reported that it’s not expressed until the 50-cell stage(http://cshprotocols.cshlp.org/content/2012/8/pdb.prot070615.full) This was used for their automated embryonic lineaging experiments. However, I see on the wormbase site that Steve Henikoff’s group did observe a his-72 promoter reporter to be active in the 26-cell stage embryo. I’m not sure how important the timing of expression for your desired promoter is. You can also vet candidate promoters using the Waterston Lab Lineagomic site, where expression patterns of a number of promoters are systematically assayed in the C. elegans embryo:
http://epic.gs.washington.edu
Thank you very much!