XB-ART-1128Gene Expr Patterns December 1, 2005; 6 (1): 3-10.
Expression of Panza, an alpha2-macroglobulin, in a restricted dorsal domain of the primitive gut in Xenopus laevis.
Alpha2-macroglobulin is a major serum protein with diverse functions, including inhibition of protease activity and binding of growth factors, cytokines, and disease factors. We have cloned and characterized Panza, a new Xenopus laevis alpha2-macroglobulin. Panza has 56-60% amino acid similarity with previously identified Xenopus, mouse, rat and human alpha2-macroglobulins, indicating that Panza is a new member of the alpha2-macroglobulin family. Panza mRNA is first detected at the beginning of neurulation in the dorsal endoderm lining the primitive gut (archenteron roof). At the completion of neurulation and continuing through the late tadpole stage, Panza is restricted to a dorsal domain of the gut endoderm adjacent to the notochord and extending along the entire anterior-posterior axis. With outgrowth of the tailbud, Panza expression persists in the chordaneural hinge at the posterior end of the differentiating notochord and extends into the floor plate of the posterior neural tube. As gut coiling commences, Panza expression is initiated in the liver, and the dorsal domain of Panza expression becomes limited to the midgut and hindgut. With further gut coiling, strong Panza expression persists in the liver, but is lost from other regions of the gut. The expression of Panza in endodermal cells adjacent to the notochord points to a potential role for Panza in signal modulation and/or morphogenesis of the primitive gut.
PubMed ID: 16275122
PMC ID: PMC1351133
Article link: Gene Expr Patterns
Species referenced: Xenopus laevis
Genes referenced: a2m a2ml1
Article Images: [+] show captions
|Fig. 2. Embryonic expression of Panza and Edd. Whole-mount in situ hybridization for Panza (A,A1,A2,C,E,E1,E2,G,I) and Edd (B,B1,B2,D,F,F1,F2,H,J) at stages 14 (A,A1,A2,B,B1,B2), 17 (C,D), 20 (E,E1,E2,F,F1,F2), 26 (G,H), and 33 (I,J). Panza expression is first detected at the neurula stage in the dorsal primitive gut (archenteron roof) extending from the oral evagination to the blastopore, with expression extending more laterally in the posterior gut. With elongation of the body axis, Panza extends along the entire anterior–posterior axis in the dorsal gut endoderm, narrower in the anterior gut and gradually broadening in the posterior gut. Panza is also expressed in the chordaneural hinge, extending into the floorplate of the posterior neural tube (arrowheads). Edd is expressed throughout the dorsal, lateral and ventral endoderm, but not in the neural tube. (A–J) Lateral views of cleared embryos with anterior left are shown. (A1–F2) Transverse sections (dorsal up) of stained embryos at the axial levels indicated by dotted lines in (A,B,E,F). fp, Floorplate; n, notochord.|
|Fig. 3. Panza expression adjacent to the notochord. (A) Double staining for Panza (blue) by whole-mount in situ hybridization and notochord (brown) by immunohistochemistry using the Tor70 monoclonal antibody. Panza is expressed in the gut endoderm adjacent to the notochord and extends around the posterior tip of the notochord into the floorplate of the posterior neural tube. (A1–A4) Transverse sections of double-stained embryos (stage 33) at the axial levels indicated by dotted lines in (A). Panza is expressed in the dorsal endoderm of the foregut at the level of the eyes (A1), in the dorsal endoderm adjacent to the notochord in the anterior midgut (A2), and in the dorsal and lateral endoderm of the posterior midgut and hindgut (A3,A4). At the level of the hindgut, Panza expression is also detected in the floorplate of the posterior neural tube (A4). Higher magnification view of a section with the hypochord clearly visible (B). Higher magnification views of Panza and notochord in the posterior end at stage 20 (C), and in the elongating tailbud at stages 33 (D) and 36 (E), showing Panza expression ventral, posterior and dorsal to the notochord. Shown are lateral views of cleared embryos with anterior left (A,C–E) and transverse views with dorsal up (A1–A4,B). de, Dorsal endoderm; e, eyes; fg, foregut; fp, floorplate; h, hypochord; hg, hindgut; mg, midgut; n, notochord; nt, neural tube; s, somite.|
|Fig. 4. Panza and Edd expression in the coiled gut and liver. In situ hybridization for Panza (A,A′,C,C′,E,E′,G,G′,I) and Edd (B,D,F,H,J) expression in guts removed from embryos at stages 40 (A,A′,B), 41 (C,C′,D), 42 (E,E′,F), 44 (G,G′,H), and 46 (I,J). Ventral (A,C,E,G) and dorsal (A′,B,C′,D,E′,F,G′,H) views with anterior left are shown. For some samples, the coiled gut was straightened before in situ hybridization and is shown with anterior left (I,J). The brown material apparent in the coiled gut shown in (J) is gut contents present before sample preparation. Arrowheads indicate the position of the liver. gb, Gallbladder; lv, liver; p, pancreas; s, stomach.|
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