Figure 1.
gpa-4 promoter expression during development assessed using recombination-mediated red-to-green fluorescent reporter: (A) Experimental system to assess the expression pattern of the
gpa-4 promoter during development. Expression of the Cre recombinase driven by the
gpa-4 promoter leads to the excision of a floxed mCherry cassette and the expression of GFP. Any cell type in which the
gpa-4 promoter has been active will thereby appear green (B) PCR across the floxed mCherry cassette using primers depicted in A, in the wild-type strain (N2), a strain containing only the floxed mCherry::GFP transgene and a strain carrying both the floxed mCherry::GFP cassette and the
gpa-4p::Cre construct. Band sizes in kb. (C) Many lineages express GFP, following excision of the floxed mCherry cassette by Cre driven by the
gpa-4 promoter during embryonic and post-embryonic development. Fluorescent compound image of an L2 larval stage animal with red (unexcised cassette) and green (excised cassette) cells. Clear expression is identified in the somatic gonad (Som. Gon.), vulval precursor cells (VPC), seam cells, body wall muscle cells, tail, and head neurons, as well as, the P lineage. *: autofluorescence of gut granules (D) Negative control animal showing no GFP expression, as they carry only the floxed mCherry cassette transgene without a Cre driver (E) Positive control animal in which Cre is active in the intestine (
elt-2 promoter): intestine-specific excision of the mCherry cassette leads to GFP expression in the gut.