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Nutritional endoderm in a direct developing frog: a potential parallel to the evolution of the amniote egg.
- Source :
-
Developmental dynamics : an official publication of the American Association of Anatomists [Dev Dyn] 2007 May; Vol. 236 (5), pp. 1259-72. - Publication Year :
- 2007
-
Abstract
- The egg of the direct-developing frog, Eleutherodactylus coqui, has 20 x the volume as that of the model amphibian, Xenopus laevis. Increased egg size led to the origin of nutritional endoderm, a novel cell type that provides nutrition but does not differentiate into digestive tract tissues. As the E. coqui endoderm develops, a distinct boundary exists between differentiating intestinal cells and large yolky cells, which persists even when yolk platelets are depleted. The yolky cells do not become tissues of the digestive tract and are lost, as shown by histology and lineage tracing. EcSox17, an endodermal transcriptional factor, did not distinguish these two cell types, however. When cleavage of the yolky cells was inhibited, embryogenesis continued, indicating that some degree of incomplete cleavage can be tolerated. The presence of cellularized nutritional endoderm in E. coqui may parallel changes that occurred in the evolution of the amniote egg 360 million years ago.<br /> ((c) 2007 Wiley-Liss, Inc.)
- Subjects :
- Animals
Anura genetics
Anura metabolism
Base Sequence
Biological Evolution
DNA, Complementary genetics
Endoderm cytology
Female
Gene Expression Regulation, Developmental
Intestines embryology
Mesonephros embryology
Ovum cytology
Species Specificity
Thyroid Hormones metabolism
Transcription Factors genetics
Transcription Factors metabolism
Xenopus laevis embryology
Anura embryology
Subjects
Details
- Language :
- English
- ISSN :
- 1058-8388
- Volume :
- 236
- Issue :
- 5
- Database :
- MEDLINE
- Journal :
- Developmental dynamics : an official publication of the American Association of Anatomists
- Publication Type :
- Academic Journal
- Accession number :
- 17436277
- Full Text :
- https://doi.org/10.1002/dvdy.21153