XB-ART-21141Brain Res Dev Brain Res June 17, 1994; 79 (2): 177-85.
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Localization of thymosin beta 4 to the neural tissues during the development of Xenopus laevis, as studied by in situ hybridization and immunohistochemistry.
Thymosin beta 4, a polypeptide of 5 kDa, is known to have capacity to regulate actin polymerization by binding to an actin monomer. Distribution of Xenopus laevis thymosin beta 4 (XT beta 4) in the developing Xenopus larva was examined by means of in situ hybridization and immunohistochemistry. Analysis with in situ hybridization revealed that XT beta 4 mRNA becomes gradually localized to the neural tissues, notochord and inner epidermis during neurula stages. Intense accumulation of XT beta 4 mRNA was observed in the ganglions of cranial nerves and in the dorsal region of the spinal cord from stage 26 and onwards. XT beta 4 immunoreactivity (XTI) was observed in larvas at all developmental stages later than stage 26, tail bud embryo. Immunoreactivity was initially distributed to the ganglion of cranial nerve V and Rohon-Beard cells. As the development progressed, the XTI appeared in other neuronal groups. By late tadpole stages (stages 42-47) the XTI was found in the pineal body, oculomotor and trochlear motoneurons of the midbrain, various neurons in the rhombencephalon, ganglions of cranial nerves V, VII/VIII and IX/X. In the spinal cord the XTI was observed in Rohon-Beard cells, dorsal root ganglion cells, motoneurons and other spinal cord neurons. Immunoreactivity was seen in both cell bodies and axons of the neurons. These findings suggest that thymosin beta 4 plays a role in the development of neurons, especially of sensory neurons.
PubMed ID: 7955316
Article link: Brain Res Dev Brain Res
Species referenced: Xenopus laevis
Genes referenced: actl6a tmsb4x
Antibodies: Tmsb4x Ab1
Article Images: [+] show captions
|Fig. 1. Photographs showing the distribution of XT/34 mRNA in the Xenopus embryos revealed by in situ hybridization. A: a mid-sagittat section of a stage-20 embryo hybridized with the XT/34 sense probe as control. No signals were seen. B: a mid-sagittal section of a stage-20 embryo hybridized with the XT/34 anti-sense probe. The XTCl4 mRNA was prominent in the neural tube, notochord and mesenchymal tissues under the skin. An accumulation of the mRNA was observed ventrally in the notochord (arrow heads). C: a midsagitta] section of a stage-34 embryo. An intense signal was located at the dorsal midline in the spinal cord (arrow heads). M, myotome; No, notochord; Nt, neural tube. Scale bars in A and B, 100 #m; in (, I mm.|
|Fig. 2, Photographs showing the distribution of XT/34 mRNA in cross sections. A,B: sections of a stage-2() embryo. In the rostral region (A), an intense signal was recognized dorsal to the neural tube, presumably in neural crest cells (arrow). In the caudal region (B), signals were distributed in the whole neural tube. C,D: sections of a stage-26 embryo, An intense signal was observed in ganglion cells of the trigeminal nerve (arrows)in the rhombencephalon (C) and cells dorsal to the neural tube in the spinal cord (D). E,F: sections of a stage-34 embryo. An intense signal was localized in ganglion cells of cranial nerves VII/VIII (arrow) at the level of the otic vesicle (El and in cells of the dorsal region in the spinal cord (F). M, myotome, No, notochord; Nt, neural tube; O, otic vesicle: R, retina. Scale bars, 100/xm.|
|Fig. 3. Microphotographs showing the distribution of XT/34 immunoreactivity (XTI) in tail bud embryos. A: a whole mount embryo (stage 26: lateral view) stained with pre-immune antiserum for control. B: a whole mount embryo (stage 26) stained with the anti-XT/34 antibody. The XTI was seen in the trigeminal nerve (arrow). C: a whole mount embryo (stage 34) stained with the anti-XT/34 antibody. Arrow indicates cranial nerves VII/VIII. Open arrow head indicates the pineal body and the solid arrow heads indicate the XTI located on Rohon-Beard cells and extramedullary cells along the spinal cord. D: a cross-section of a stage-26 embryo. The XTI was seen in ganglion cells of the trigeminal nerve. E-H: Cross sections of a stage-34 embryo. E: an intense XTI observed in ganglion cells of the trigeminal nerve (arrows). F: the XTI observed in the ganglions of cranial nerves VII/VIII (arrow head) and their proximal axons entering the lateral tract of the rhombencephalon (arrow): G: an intense XTI localized at the pineal body. H: an intense XTI seen in Rohon-Beard cells and extramedullary cells (arrow). M, myotome; No, notochord; Nt, neural tube; O, otic vesicle; R, retina. Scale bars, in A-C, 1 mm; in D-H, 100 ~m.|
|Fig. 4. Microphotographs showing the distribution of XTI in cross sections of the late tad pole stages. Levels of cross sections (A-E) are indicated at right bottom. A: a section through the midbrain of a stage-42 embryo. The XTI is seen in the oculomotor nerves (arrows) and motoneurons. B-E: cross sections of a stage-47 embryo. B: Mauthner cell and other neurons showing XTI in the rhombencephalon. Inset: higher magnification of the Mauthner cell. C: the XTI in ganglion cells of cranial nerves IX/X. D: retinal ganglion cells showing XTI (arrows) E: the XTI seen in motoneurons, dorsal root ganglions and nerve fibers coursing between myotomes (arrows). L, lens; M, myotome: No, notochord; Nt, neural tube. Scale bars, 100 k~m.|