Fig. 2

Expression atlas of AAAP-536 and APC-8904 genes in asexual A. pisum during symbiont invasion. Staged embryos hybridized with DIG-labeled antisense (a–h) and sense riboprobes (i, j) of AAAP-536 and APC-8904. Signals were revealed by NBT/BCIP brown precipitates. All embryos are displayed with anterior of the germaria to the left. Arrowheads mark AAAP-536-positive signals outside of the bacterial mass. Dashed lines indicate the location of germ cells. Arrows indicate regions of endosymbiotic bacterial mass that are not concomitant with AAAP-536 and APC-8904 signals. a–d Incorporation of the maternal endosymbiotic bacteria (stage 7), germband invagination (stages 8–9), and germband bending (stage 10). Notably at stages 8–9 most transcripts of AAAP-536 were detected in the anterior region of the bacterial mass. Insets in b–d are magnifications of the AAAP-536 transcripts detected outside the bacterial mass (arrowheads). e–h Expression of APC-8904 was detected in the bacterial region such that the intensity of the signal was strongest in the anterior region of the bacterial mass (stages 8–10). i, j Stage 7 embryos hybridized with sense riboprobes. No signal was detected with AAAP-536 sense riboprobes, but ubiquitous signals were detected with APC-8904 sense riboprobes. k Illustration displaying presented developmental stages. In situ signals of AAAP-536 and APC-8904, location of germ cells, and location of Buchnera are indicated by the color key. Scale bars are all 20 μm. am amnion, bc Buchnera symbionts, cl cephalic lobe, cs central syncytium, eflc enlarged follicle cells, gc germ cells, ig invaginating germband, s serosa, sn syncytial nucleus, st stage