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FROM:
Nandan L. Nerurkar (1), L. Mahadevan (2), and Clifford J. Tabin (1)
(1) Department of Genetics, Harvard Medical School, Boston, MA 02115
(2) School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138
“BMP signaling controls buckling forces to modulate looping morphogenesis of the gut”, Proceedings of the National Aademy of Siences of the USA (PNAS) February 28, 2017 114 (9) 2277-2282, https://doi.org/10.1073/pnas.1700307114
“BMP”= “Bone Morphogenetic Proteins”
SIGNIFICANCE: During embryogenesis, the dramatic transformation from a seemingly disorganized mass of cells into the fully patterned adult form necessitates stereotyped regulation of forces at the genetic and molecular level. Although great progress has been made in understanding how gene expression and signaling generate biological pattern, little is known about how molecular cues organize forces to sculpt physical patterns during development. The present work identifies BMP signaling as a key pathway in controlling looping of the small intestine, a process driven by mechanical buckling due to elongation of the intestine against the constraint of a neighboring tissue, the dorsal mesentery.
FIGURE CAPTION:
BMP activity in the dorsal mesentery correlates with differential growth across development and between species. (A) Phospho-Smad 1/5/8 staining in the chick dorsal mesentery at early (E10) to mid (E12) and late (E16) looping stages. (B) Phospho-Smad 1/5/8 staining in the zebra finch dorsal mesentery at early (E9) to mid (E10) and late (E11) looping stages. All sections are from the distal jejunum and proximal ileum. For each, whole-mount bright field of the intestine is shown at Left (scale bar: 1 mm); immunofluorescent staining for phospho-Smad (red) and DAPI counterstain (blue) is shown at Center (scale bar: 100 µm), and the boxed region indicates the isolated phospho-Smad signal magnified at Right (scale bar: 10 µm). dm, dorsal mesentery; gt, gut tube.
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