Fig. 3. Expression of mog-6. (A) Northern analysis of mog-6 RNA. (A, left) mog-6 RNA levels vary throughout development: E, embryos; L1 to L4, larval stages; A, adult. CeIF was the loading control. Right, RNAs from adult wild-type and glp-1 mutants were probed for mog-6 and act-1 (loading control). (B) Expression of mog-6::gfp. Top, the mog-6 gene was fused in frame with gfp. Exons are represented by boxes. The 5' and 3' flanking sequences are those of mog-6 (pAP6 in Fig. 1). Bottom, MOG-6::GFP is found in nuclei of the intestine (black arrowheads), uterus (gray arrowheads) and other somatic tissues. The black arrow points toward the vulva. Anterior is to the left. (C-I) Immunocytochemistry. (C) In wild-type L4 larvae, MOG-6 is expressed in germline nuclei throughout the mitotic and the meiotic regions. (D) To visualize nuclei, the same worm was stained with DAPI. Anti-MOG-6 antibodies stain somatic nuclei (intestine, white arrows in C,D) and mitotically or meiotically dividing germline nuclei (arrowhead in C,D). (E) Drawing of the germline shown in (C,D). Nuclei of sperm and spermatocytes are shown in white. (F) MOG-6 and MEP-1 in intestinal nuclei. The nucleolus is visible by DIC microscopy (arrow) and took up lower amounts of DAPI than the remainder of the nucleus. MOG-6 and MEP-1 are present throughout the whole nucleus, including the nucleolus. (G) MOG-6 in larvae. L3, left; L2 right; L1 before hatching, below. (H) Expression of MOG-6 in a feminized adult germline. MOG-6 is found in all nuclei, including those of mature oocytes (arrow). (I) DAPI staining of the same germline; the condensed chromosomes of accumulating oocytes are visible (white arrow). The asterisk shows the distal end of the germline. Scale bar: 20 µm.