- Expr2559
Intense GFP signals were detected as lines from the pharyngeal region of the digestive tubes in addition to other types of cells. The pharyngeal region of the digestive tubes can be subdivided into four portions: procorpus, metacorpus, isthmus, and terminal bulb. Among them, the procorpus and isthmus portions are elongated. In both portions, three parallel GFP-positive lines (occasionally one or two additional lines in the isthmus portion) were observed to run longitudinally and to surround the interior lumen. Close inspection revealed that each of these thick lines occasionally resolved into two thinner lines. These findings suggested that CLC-1 is expressed in the epithelial cells of the pharyngeal region of the digestive tubes and is concentrated at the intercellular junctions located at the most apical portion of the lateral membranes.
- Expr2407
After the comma stage in embryos, expression of VHA-6 changed. In 2-fold embryos, VHA-6 was limited to the intestine. Such intestinal expression was also observed in larvae and adults. The C. elegans intestine comprises a tube formed from 20 cells with microvilli on their apical surface. Furthermore, VHA-6 was clearly found at the junction between the pharynx and the intestine.
- Expr9949
EGG-6::GFP was expressed in a subset of epithelial cells, including epidermal, vulval and rectal cells and the excretory duct and pore. EGG-6::GFP was also observed in some neurons. Expression began around the ventral enclosure stage of embryogenesis and continued through larval development, but then decreased in adulthood. Expression was absent from internal epithelia such as the gut and pharyngeal tubes.
- Expr9948
LET-4::GFP was expressed in a subset of epithelial cells, including epidermal, vulval and rectal cells and the excretory duct and pore. Expression began around the ventral enclosure stage of embryogenesis and continued through larval development, but then decreased in adulthood. Expression was absent from internal epithelia such as the gut and pharyngeal tubes. LET-4::GFP was transiently expressed in the excretory canal cell at the 1.5-fold stage, but no longer visible in this cell by hatch. Notably, with the exception of the canal cell, the epithelia that expressed LET-4 were those that would eventually become cuticle-lined.
- Expr16132
GFP::MLS-2 expression became detectable around the 50-cell stage of embryogenesis and was restricted to specific, reproducible sublineages of the AB blastomere, most of which gave rise to neuronal and/or glial descendants. GFP::MLS-2 was also expressed in the duct and pore lineages, but was never observed in the canal cell. In 3/3 movies, we saw that expression of GFP::MLS-2 initiated in the grandparents of the duct and pore cell. GFP::MLS- 2 expression persisted in the duct and pore cells through the ventral enclosure and 1.5-fold stages of embryonic development, during which time fates are specified via EGF-Ras- ERK signaling and the duct and pore cells stack and form tubes (Abdus-Saboor et al., 2011). By the first larval stage of development, when the duct and pore cells have achieved their mature morphologies, GFP::MLS-2 was no longer detected in the duct and pore cells.
- Expr12833
The LIN-23 protein is present both in all blast cells of embryos and in the wild-type germline. LIN-23 is present in the germline from the tip of the distal arm to the maturing oocytes. Its abundance seems relatively similar between the distal and proximal zones; however, its localization is concentrated within cytosol and is relatively excluded from nuclei. The distal region of the gonad is a syncytial tube with the germline nuclei packed around the outside with a hollow core. We find that LIN-23 is concentrated throughout the core and in the cytosolic spaces between the nuclei and is either absent from, or present at a much reduced level, in the nuclei themselves. Within developing oocytes in the proximal region of the gonad, it is also more abundant in the cytoplasm than nuclei. An interesting observation was the differential localization of LIN-23 in the cells of the early embryo. It is generally distributed throughout the cytosol, but its localization is dynamic being differentially excluded from the nucleus for much of the cell cycle, but a fraction of it accumulates to the nuclear compartment late in the cycle shortly before cell division. In the embryos shown, the nuclear compartment accumulation of LIN-23 is seen in a late AB blastomere but is absent in a slightly younger AB blastomere. Similarly, it can be seen in both the ABa and ABp blastomeres but absent from the nuclei of the EMS and P2 blastomeres. Because the ABa and ABp blastomeres divide slightly earlier than EMS and P2, they are inevitably later in the cell cycle. However, this pattern is not lineage dependent.