Figure 2.
slt-1::GFP Expression Pattern. (A) A GFP fusion gene containing 4 kb of
slt-1 upstream sequence and the first two codons of the
slt-1 coding region was used to analyze
slt-1 expression.(B) Comma stage embryo.
slt-1::GFP is first detected in a cap of anterior epidermal cells (arrow). For embryos in (B)-(D), anterior is at top, and the embryo curves so that posterior is at left.(C) Two-fold stage embryo. Increased expression in the anterior cap of epidermal cells is observed (arrow) in addition to
slt-1::GFP expression in many pharyngeal cells (white arrowhead, P). The asymmetric expression of
slt-1::GFP in body wall muscles begins at this stage in the most posterior dorsal muscles (M).
slt-1::GFP was also present in the anal sphincter muscle, located in the tail of the animal (black arrowhead, A).(D) Antibody staining of a 1.5-fold
slt-1::GFP-expressing embryo with anti-GFP (green) and MH27 antiserum against the epithelial junction protein JAM-1 (red). Left, the epithelial cells at a superficial focal plane in the embryo. The
hyp5 cell, which has fused to form a ring (arrow), serves as a reference point for identifying
slt-1::GFP-expressing cells. Right, a medial focal plane of the embryo with robust
slt-1::GFP expression in the head. Two
hyp4 epidermal cells, which are located directly anterior to the
hyp5 cell, express
slt-1::GFP (arrowheads). Posterior to
hyp4 are other hyp cells, some pharyngeal cells, and dorsal muscles in the tail (M) that also express
slt-1::GFP.(E) L1 stage larva. Expression of
slt-1::GFP is prominent in all dorsal body wall muscles (arrows). The BDU neuron (white arrowhead) also expresses the transgene. The anal sphincter muscle (black arrowhead) continues to express
slt-1::GFP. Weak expression is present in ventral body wall muscles just anterior of the anal sphincter muscle. Strong expression persists in the head. Anterior is to the left, dorsal at the top.(F) The head of an adult animal.
slt-1::GFP expression is observed in the RIH and RMED neurons (arrows), which send axons into the nerve ring (arrowhead). Hypodermal (H), muscle (M), and pharyngeal (P) expression continues in the adult. Anterior is to the left, dorsal at the top. Scale bars, 10 μm.