Expression of Brachyury during development of the dendrobatid frog Colostethus machalilla.
The expression of Brachyury (Bra) during development of Colostethus machalilla was analyzed with a polyclonal antibody. The observed molecular mass of Bra was of 48 kDa, as in Xenopus laevis. During cleavage, low levels of Bra were expressed. In contrast, in the blastula Bra became up-regulated, and Bra protein was present in a wide ring of surface cells. The surface expression of Bra disappeared in the gastrula, and a new ring of Bra-positive nuclei was detected in deep cells around the closing blastopore. The C. machalilla external and internal rings of Bra-positive nuclei apparently mark the prospective mesoderm in the blastula and gastrula, respectively. The two Bra expression rings were dissociated in time in the fairly slow developing embryos of this frog. Brachyury expression in the notochord became visible only after the blastopore closed, in contrast with X. laevis. In addition, Bra expression in the notochord indicated that dorsal convergence and extension occurred after blastopore closure. The C. machalilla Bra-positive notochord was originally exposed on the gastrocoel roof, in agreement with a superficial component of the prospective mesoderm.
Benítez
María-Soledad
MS
Departamento de Ciencias Biológicas, Pontificia Universidad Católica del Ecuador, Quito, Ecuador.
Del Pino
Eugenia M
EM
D000818:Animals; D002025:Bufonidae / Q000196:embryology; D005326:Fetal Proteins; D018507:Gene Expression Regulation, Developmental; D008648:Mesoderm / Q000378:metabolism; D009672:Notochord / Q000378:metabolism; D011898:Ranidae / Q000196:embryology* / Q000378:metabolism*; D013045:Species Specificity; D020825:T-Box Domain Proteins / Q000096:biosynthesis* / Q000235:genetics; D013997:Time Factors; D014982:Xenopus laevis / Q000196:embryology; D000098908:Brachyury Protein
D005326:Fetal Proteins; D020825:T-Box Domain Proteins; D000098908:Brachyury Protein