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Description: Fig. 1. Endogenous patterns of RNA localization of dnd, nos1, vas, and dazl RNAs during the first cell cycle. Animal views of embryos fixed at progressively older stages of development (A-D: 15 min p.f.; E-H: 30 min. p.f.; I-L: 45 min p.f.) and labeled using FISH to detect germ plasm RNAs (dnd (A, E, I); nos1 (B, F, J); vas(C,G, K); dazl (D, H, L). (A-D) Immediately after fertilization, dnd, nos1, and vas RNA aggregates can be observed as a band at the animal pole, while dazl RNA aggregates are not initially present in the animal pole. (E-H) During the initiation of furrow formation, RNA aggregates fordnd, nos1, and vas begin to be recruited as a rod at the forming furrow (arrows in E-G). At this stage, dazl RNA is not yet detectable at the furrows (H). (I-L) As the furrow matures, there is an increase in the amount of dnd, nos1, and vasRNAs recruited at the furrow, and dazlRNA becomes detectable at the furrow (arrows in I-L). Scale bar in panel (L) represents 100 μmThus, although all four RNAs are recruited to the forming furrow, RNAs for dnd, nos1, and vas are already present in the animal pole in the freshly laid egg, while dazlRNA arrives to the animal pole from the vegetal region at a later stage. Based on their different times of appearance at the animal region, we refer to the dnd, nos1, and vas RNAs as the early animal germ plasm RNAs, while dazl is also referred to as a vegetally localized germ plasm RNA.
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