Worm Breeder's Gazette 11(3): 75
These abstracts should not be cited in bibliographies. Material contained herein should be treated as personal communication and should be cited as such only with the consent of the author.
As was the case with the vulva, the uterus proved considerably easier to reconstruct in the L4 than the adult. It is an elaborate structure made up of (as is most of C. elegans) a sequence of epithelial rings. The late L4 uterus seems to be completely formed being almost identical in structure to that of the adult apart from the presence of eggs. The uterus consists of three main components: a group of mononucleate cells that form an interface to the vulva (uv1-3); a large 'H' shaped multinucleate cell that attaches the uterus to the seam cells laterally (use) and a sequence of four toroidal multinucleate cells (ut1-4) on each side that make up the body of the uterus. The four uv1 cells attach the uterus to the F cell of the vulva. They have thin elongated processes and probably are the additional cells (i.e. apart from the VCs) that light up in Chris Li's Anti-FMRFamide stained preparations. The uv1 cells attach to the uv2 cells and also to a thin, sheet-like process of the use cell which forms a hymen blocking the entrance to the uterus. The attachments are by means of desmosomes which form an unusual 'Y' shaped junction in this region. The central sheet of the use cell is therefore unusual in that it is ambiguous with respect to its basal and apical domains. Judith Kimble has suggested that the anchor cell forms the barrier between the uterus and vulva; it therefore seems likely that the anchor cell eventually fuses with and becomes part of the use cell, which could explain why this cell has an extra nucleus on one side. The basement membrane that surrounds the gonad is significantly thicker in the vicinity of the lateral extremities of the use cell, and it is in these regions that the gonad is attached to the seam cells. The nine nuclei of the use cell are displaced away from the attachment regions adjacent to the vulva. The uv1 cells are attached via uv2 and then uv3 to the first of the toroidal uterine cells. There is an additional cell with 2 nuclei (du) that makes up the dorsal part of the uterus opposite the vulva (see Fig. on vulva note) which is also attached to the first toroidal uterine cell (ut1). The ut1, ut2, ut3 and ut4 uterine cells have 4, 4, 4 and 6 nuclei respectively; ut6 is connected to the spermathecal valve. The apical faces of the ut cells are situated on the inner surface of the toroids and make up the lumen of the uterus. [See Figure 1]