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Figure 4. Craniofacial skeleton defects in Rbfox2 mutant embryos. ; Alizarin red and Alcian blue stainings for ossified and chondrified tissues, respectively, of control (A–B), (D–E), (G), and I–J) and Rbfox2Pax3-CKO (C), (F), (H), and (K) skeleton at E17.5 (n = 8 controls, n = 6 Rbfox2Pax3-CKO). Alizarin red and Alcian blue stainings of control (L), (N), (P), and (R) and Rbfox2Wnt1-CKO (M, O, Q and S) skeleton at E18.5 (n = 8 controls, n = 5 Rbfox2Wnt1-CKO). Neural crest and mesoderm contribution to craniofacial bones are represented in green and pink color respectively (A, D and I). Dorsal (A–C and L–M), lateral (D–F and N–O) and ventral (I–K and R–S) view of skulls. Both Rbfox2Pax3-CKO (C), (F), (H), and K) and Rbfox2Wnt1-CKO (M), (O), (Q), and S) embryos demonstrate severe hypoplasia and diminished ossification of many neural crest-derived bones. Asterisks (*) represent the missing PPPL bone in Rbfox2 mutant embryos (K and S). AS, alisphenoid; BO, basioccipital; BS, basisphenoid; EO, exoccipital; F, frontal bone; IP, interparietal; MD, mandible; MX, maxilla; N, nasal; NC, nasal capsule; P, parietal bone; PL, palatine; PMX, premaxilla; PPMX, palatal process of maxilla; PPPL, palatal process of palatine; PPPMX, palatal process of premaxilla; PT, petrous part of temporal bone; SO, supraoccipital; SQ, squamous.

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Figure 1. Reconstruction of Parhyale embryogenesis with multi-view LSFM (see also Figure 1—video 1 and 2). ; (A) Transgenic Parhyale embryo with H2B-mRFPruby-labeled nuclei mounted with fluorescent beads (green dots) for multi-view reconstruction. The embryo was imaged from the indicated 5 views with 45˚ rotation around the AP axis between neighboring views. Panels show renderings of the acquired views with anterior to the left. (B) Raw views were registered and fused into an output image rendered here in different positions around the DV axis. (C–K) Each panel shows a rendering of the embryo at the indicated developmental stage in hours (h) after egg-lay (AEL) and the corresponding time-point (TP) of the recording. Anterior is to the left and dorsal to the top. Abbreviations: first antenna (An1), second antenna (An2), mandible (Mn), maxilla 1 (Mx1), maxilla 2 (Mx2), thoracic appendages 1 to 8 (T1–T8), pleonic (abdominal) appendages 1 to 6 (P1–P6) and telson (Te). Color masks indicate the cells contributing to Mx2 (blue), T1 (green), T2 and T3 (light and dark yellow) and T4 limb (magenta). (C) Embryo at mid-germband stage S13 according to (Browne et al., 2005). The ventral midline is denoted with the dotted line. (D) S15 embryo. Germband has extended to the posterior egg pole and the first antennal bud is visible anteriorly. (E) S18 embryo with posterior flexure. Head and thoracic appendages have bulged out up to T4. (F) S19 embryo with prominent head and thoracic appendage buds up to T6. (G) S20 embryo continues axial elongation ventrally and anteriorly. Appendage buds are visible up to P3. (H) S21 embryo. Segmentation is complete and all appendages have formed. The Mx2 has split into two branches (blue arrowheads) and the T1 limb has developed two proximal ventral outgrowths (green arrowheads). (I) Embryo at stage S22, (J) S23, and (K) S24 showing different phases of appendage segmentation. Dorsal outgrowths at the base of thoracic appendages, namely coxal plates (orange arrowheads) and gills (red arrowheads), are indicated in T2, T3 and T4. Scale bars are 100 µm.

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Figure 9. Comparison of LES1 maxilla to the DH1 holotype maxilla of H. naledi. ; In each pair, LES1 is on the left and DH1 on the right. Top left: anterior view. Top right: right (LES1) and left (DH1) lateral view. Bottom: occlusal view. Scale bar = 2 cm.

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Figure 1. Four-bar linkage systems have evolved independently multiple times across animals and are comprised of four rotatable links that transmit motion and force. ; (A) Four-bar linkages consist of a fixed link (black) and three mobile links: input (orange), output (red), and coupler (blue). (B) In the raptorial appendages of mantis shrimp (Stomatopoda), rotation of the input link (meral-V, m-V, which is part of the merus segment, me) causes the output link (carpus, ca) to rotate outward, which then rapidly rotates the dactyl (da). (C) In the oral four-bar system that evolved independently in labrid and cichlid fishes, the input link (lower jaw, lj) rotates ventrally, causing rotation in the nasal (na) and in the output link (maxilla, mx), resulting in premaxillary (pmx) protrusion. (D) In the opercular four-bar linkage system of centrarchid fish, the input link (opercle and subopercle, op) swings posteriorly, as does the interopercle (iop). This motion is transmitted to the output link (retroarticular process in the mandible, ra), which causes the mandible to rotate ventrally and open the lower jaw. (B–D) Dashed lines denote the closed configuration of input (orange), output (red), and coupler (blue) links, whereas solid lines denote their open configuration following motion. Arrows denote the direction of motion. Distal/anterior is to the right and dorsal is toward the top of the page.

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Figure 2—figure supplement 1. Schematic drawing of the recovered skeletal elements of Miopetaurista neogrivensis from Abocador de Can Mata locality ACM/C5-D1 (IPS56468) in the position that they were found. ; Note that some elements, such as the femora, pelvis and tail vertebrae are in anatomical connection. This scheme has been drawn based on multiple pictures taken during the preparation process. Not all the elements shown here were visible at the same time, many of them being unearthed during the separation of the specimen from the matrix. ab, auditory bulla; c3, cervical vertebra 3; ca, caudal vertebra; cl, clavicle; fe, femur; hu, humerus; il, ilium; im, ischium, l3–l6, lumbar vertebrae 3 to 6; ma, mandible; mt2–5, metatarsals 2 to 5 in anatomical connection; mx, maxilla; pb, pubis; pl, palatine; px, premaxilla; r, rib; ra, radius; ti, tibia. For a complete catalogue of the recovered elements of the partial skeleton IPS56468 see Table 1. Scale bar is 5 cm.

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Figure 7—figure supplement 1. Udorn replicates preferentially in the rostral naso- and maxilla-turbinates. ; Ifnar1−/− Ifnlr1−/− mice were intranasally infected with 105 PFU of Udorn and sacrificed 24 h later. Heads of animals were collected, processed for cryosections and subjected to Periodic acid–Schiff staining (top panel) or immune-stained (bottom panels) for EpCAM (red), influenza virus antigen (green) and DAPI (blue).

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Figure 3. Shh signal from the brain induces a posterior part of a nasal capsule. ; (A) Model of overall shape resulting from the excision of Shh from the floor plate using Nkx2.2-Cre/Shhfloxed/floxed shows visible phenotype in the E12.5 mutant embryo comprising, for instance, from the cleft of upper lip, non-prominent or missing nasal vestibule and diminished curvature of the snout. (B–C, E–F) micro-CT scans-based 3D reconstructions of chondrogenic mesenchymal condensations in E12.5 mutant and control embryos. Note the missing posterior part of the developing nasal capsule and the missing septum in the mutant. (D) best-fit computed comparison of the overall shape and size of mutant and control embryo. (G–H) 3D models of chondrocrania of mutant (Nkx2.2-Cre/Shhfloxed/floxed) and control embryo, analyzed at E15.5. Among the main differences are missing frontal part of nasal cartilage, missing lateral parts of developing nasal capsule, malpositioned asymmetric cartilage, not fully closed foramina for pervading nerves and vasculature and various disconnected cartilaginous segments. (I) Segmented cartilage and bones projected in the overall shape of the head of mutant (bottom) and control (upper) embryo. Note the malpositioned incisors in the maxilla of the mutant and missing part of the frontal nasal capsule formed by the bone. (J) Wall thickness analysis of the cartilages in the E15.5 head of mutant (bottom) and control (upper) embryo show no evident differences in the thickness of formed cartilage.

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Figure 2. Holotype specimen of Homo naledi, Dinaledi Hominin 1 (DH1). ; U.W. 101-1473 cranium in (A) posterior and (B) frontal views (frontal view minus the frontal fragment to show calvaria interior). U.W. 101-1277 maxilla in (C) medial, (D) frontal, (E) superior, and (F) occlusal views. (G) U.W. 101-1473 cranium in anatomical alignment with occluded U.W. 101-1277 maxilla and U.W. 101-1261 mandible in left lateral view. U.W. 101-1277 mandible in (H) occlusal, (I) basal, (J) right lateral, and (K) anterior views. Scale bar = 10 cm.

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Figure 2—figure supplement 1. The amnion and serosa form a persistent bilayer comprised of two morphologically distinct epithelia, including in the anterior-ventral rupture competence zone. ; Although EGFP intensity varies between cells, EGFP signal for a single EE tissue type labels all cells within a continuous epithelial sheet. Moreover, the amnion and serosa have strikingly different cellular morphologies, enabling cells of both tissues to be distinguished, with the serosa overlying the amnion. (A–C) Both EE tissues can be discerned as continuous epithelia within the rupture competence zone (shown after the completion of germband retraction, at 44–48 hr after egg lay). Shown are two examples with serosal EGFP (A–B) and one with amniotic EGFP (C, reproduced from main text Figure 2D, for comparison). 'Overview' images show lateral, ventral, and ventral-lateral views of maximum intensity projections (A1,B1,C1, respectively) with anterior left and the region of interest around the head appendages indicated by the blue boxed region (due to the curvature of the egg, only the regions actually visible in high-magnification projections of thinner z-stacks are indicated). 'Merge' images (A2,B2,C2) show maximum intensity projections of the indicated region, labeled for F-Actin (red, phalloidin), nuclei (blue, DAPI), and the specified EE tissue (green, EGFP). Note that embryonic-specific signal (F-Actin and DAPI signal for small cells not in contact with the tissue at the egg surface) was manually deleted from deeper optical sections with the freehand selection tool in ImageJ before rendering the projected images shown here. 'Schematic' images (A3,B3,C3) show cell and nuclear outlines. Cell outlines were determined by EGFP signal (for A3,B3,C3) and F-Actin signal (for C3, for serosal outlines only). Nuclear outlines were determined by EGFP signal or DAPI (for all EGFP-negative nuclei only). Serosal cells are shown in cyan or blue; amniotic nuclei and cells are shown in orange or white. Dashed outlines highlight individual serosal (red) and amniotic (orange) cells, which are also labeled by arrows of the same color in the single-channel micrographs for EGFP (A4,B4,C4) and F-Actin (A5,B5,C5). Strong F-Actin signal correlates with serosal cell shape (compare A4,A5 and B4,B5), such that F-Actin signal can be used to infer serosal cell shape even when that tissue is not labeled with EGFP (C3,C5). Furthermore, the F-Actin-inferred serosal cell outlines correspond to EGFP-negative nuclei in the amnion enhancer trap line (C3). Note that in order to preserve anterior-ventral EE tissue structure and topography, the specimens presented here (A–C) are still within the vitelline membrane. After fixation, embryos were cut in half (transversely) with a razor blade to allow the phalloidin and DAPI staining reagents to penetrate into the sample. (The EGFP is the endogenous signal.) (D–E). For over a day prior to rupture, no cell mixing or change in cell number occurs in either the serosa (D) or the amnion (E). Selected stills from time-lapse movies are shown at the times indicated relative to rupture (at 30°C, z-stacks acquired every 2 min), in anterior aspect and oriented with the ventral region uppermost, with light sheet illumination coming from above. Individual nuclei were tracked hourly (uniquely colored tracks), showing the static nature of serosal cells until the time of rupture, while amniotic nuclei move much more within the cells and the amniotic tissue itself shifts slightly anterior-dorsally. The initial opening at the time of rupture is indicated with an asterisk (D4,E4). Axes were determined based on weak embryonic signal (D5,E5; the withdrawing edge of the amnion is still visible in E5). Images shown here are maximum intensity projections with gamma corrections 0.5 (serosa) and 0.7 (amnion) as well as brightness correction to accommodate for changes in signal intensity of these lines during development (see Figure 1—figure supplement 1 and Koelzer et al., 2014). For these specimens, cellular details at the time of rupture are shown in main text Figure 4D–E. Acquisition details are specified in Supplementary file 1. (F) The bilayer arrangement of the amnion and serosa can also be seen in transmission electron micrographs of sagittal sections (examined after the completion of germband retraction, at 44–48 hr after egg lay; see also main text Figure 2B–C). The red box on the semithin section (1 µm thick, stained with toluidine blue) approximately indicates the anterior-ventral region shown in F2–F3. The arrow highlights an intercellular junction within the serosa (F2), and false coloring highlights the continuity of the two distinct epithelial layers (F3). Both EE tissues have very flat cells, with an apical-basal thickness of only ~200 nm in the amnion and ~450 nm in the serosa, in the aponuclear region shown here. Ultrathin sections (50–100 nm thick) were cut with an 'Ultra' diamond knife on a Leica Ultracut UCT microtome, and examined with a Zeiss EM 109 electron microscope. Scale bars are 50 µm (A1,B1,C1,D1–D5,E1–E5), 20 µm (A2–A5,B2–B5,C2–C5), and 1 µm (F2–F3). Abbreviations: An, antenna; Am, amnion; D, dorsal; H, head; L, left; Lr, labrum; M, mandible; Mx, maxilla; R, right; Ser, serosa; T2, second thoracic segment; V, ventral; Vm, vitelline membrane.

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A common cis-regulatory variant impacts normal-range and disease-associated human facial shape through regulation of PKDCC during chondrogenesis

• Authors : Mohammed, Jaaved; Arora, Neha; Matthews, Harold S ...

• Source: eLife ; volume 13 ; ISSN 2050-084X

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