Hi, I am looking for promoters which can specifically drive expression in the MC or M3 motoneurons of the pharynx. Do you know of any, or perhaps promoters which drive expression in a small subset of pharyngeal neurons that includes one or other of the cells? I’m not so worried about any extra-pharyngeal expression as long as MC and/or M3 are the only pharyngeal cells that express. Many thanks for you help!
Hi,
There are a few websites you might try:
Wormatlas has pages on the MC (suggesting you try flp-21 and cholinergic reporters) and M3 (suggesting you try glt-1, flp-18, and nlp-3).
Wormbase has pages on the MC (giving no suggestions) and the M3 (suggesting glr-8 and flp-18).
Shawn Lockery assembled a list of reported expression patterns some time ago (I don’t know if it’s up to date), naming cch-1 for the MC and ceh-2, egl-36, and glt-1 for the M3.
Ian Hope has a database of expression patterns. I don’t seem to be able to access at the moment and so I don’t know whether it contains suggestions for the MC or the M3.
One thing to keep in mind if none of these patterns are sufficiently restricted for your application (and some of them clearly are not) is that you might be able to use a split-gfp approach beween two reporters with partially overlapping patterns of expression.
You can also use the WormBase ontology browser to search for genes expressed in specific cells or tissues. Search for M3 returns 21 genes:
http://www.wormbase.org/db/ontology/browse?query=WBbt:0003754;query_type=term_id;ontology=ao;details=on;children=on;expand=1
and the one for MC - 16:
http://www.wormbase.org/db/ontology/browse?query=WBbt:0003638;query_type=term_id;ontology=ao;details=on;children=on;expand=1
If you click on the ‘genes, annotations’ link next to M3 or MC, you will see a list of genes expressed in these cells. From there, you can continue to expression pattern report pages to assess whether the pattern is specific enough for your purposes.
Igor.