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Figure 2 | EvoDevo

Figure 2

From: Posterior localization of ApVas1 positions the preformed germ plasm in the sexual oviparous pea aphid Acyrthosiphon pisum

Figure 2

Localization of ApVas1 in the posterior region of newly laid eggs. Staining was performed on fertilized eggs collected within 16 hAEL. From 0 to 16 hAEL, embryos underwent 10 consecutive nuclear divisions. In each panel the nuclear cycle is highlighted in the upper right corner. DNA staining of bacteria (b) was detected in the posteriormost region of all egg chambers. (A, B) Second to fourth nuclear divisions. Asterisks mark the locations of cleaved nuclei in the shown focal plane. Localization of ApVas1 was not visualized. (C) Fifth nuclear division. Localization of ApVas1 (bracket) was first identified in the posterior region, anteriorly to the bacteria. (D, E) Eighth nuclear division. (D) and (E) are the same preparation but shown at two different focal planes. In (D), with the middle region of the egg in focus, most cleaved nuclei were observed but the ApVas1 stripe (bracket) was barely detected. In (E), with the egg cortex in focus, nuclear staining in the middle region was absent but the ApVas1 stripe (bracket) could be clearly identified. (E’) Schematic illustration indicating that cleaved nuclei have not reached the cortex region where ApVas1 is localized. (F, G) Ninth and tenth nuclear divisions. In contrast to eggs undergoing the eighth nuclear cycle, dividing nuclei could be observed in the cortex from the ninth nuclear cycle onward. In addition, the divisions began to progress in waves - nuclei located in the posterior third of the egg proceeded into anaphase but other nuclei remained at interphase or prophase. (G’) Schematic illustration indicating that some cleaved nuclei have reached the cortex region, being co-localized with the ApVas1 signals. Scale bars: 100 μm.

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