Widespread VPS-52 expression was detected in cytoplasmic puncta of many somatic tissues from early embryos on. In particular, VPS-52 is expressed in temporal continuity at all larval stages in the vulval and seam cells.
miR-52 GFP reporter was expressed most widely in hypodermal, muscle, neural, and interstitial cell types in both embryos and larvae. mir-52 was most strongly expressed in the pharynx and anterior embryo but was detectable in most other tissues.
Staining is first observed in comma stage embryos and is primarily found at regions of contact between adjacent muscle cells. Some intracellular staining of body-wall muscle cells is also observed, but neither sera stain the underlying hypodermis. Between the comma and 1.5-fold stages, staining spreads from regions of cell-cell contact over the basal face of each muscle cell, where the basement membrane is located. In older embryos, differences in staining are observed with GM1 and GM3. Beginning at the 1.5-fold stage, GM1 stains the posterior end of the pharynx. The anterior pharynx begins to stain somewhat later. By the 3-fold stage, GM1 staining surrounds the pharynx from the anterior margin to the pharyngeal-intestinal valve. GM1 also stains the anal sphincter and depressor muscles at this stage. UNC-52 is specifically associated with contractile tissues in C. elegans and is not found in the basement membranes lining the pseudocoelom or surrounding the intestine. GM3 only stains the body-wall muscles and does not stain the pharynx or anal muscles at any stage of embryonic development. Both GM1 and GM3 stain the body-wall muscles in embryos, larvae, and adults. In larvae and adults, these antisera stain the dense bodies, M-lines, and muscle cell margins, in addition to the basement membrane underlying the muscle quadrants. Both antisera also stain the basement membranes associated with the pharyngeal, anal, and sex-specific muscles in adult animals. GM1 staining of the pharynx, body-wall muscles, and reproductive muscles is shown. UNC-52 is concentrated over focal adhesion-like structures in the pharyngeal muscles. GM1 staining surrounds the pharynx from the anterior margin to the pharyngealintestinal valve, and muscle cells within the terminal bulb stain with a punctate pattern. This punctate staining pattern was not observed in animals prepared by freeze-fracture.
GFP expression driven by vps-52 promoter is visible in all cell types: pharyngeal, intestine, distal tip cell, coelomocytes, body wall muscles, and neurons.