TY - JOUR
T1 - Long- and short-range signals control the dynamic expression of an animal hemisphere-specific gene in Xenopus
AU - Mir, Adnan
AU - Kofron, Matthew
AU - Heasman, Janet
AU - Mogle, Melissa
AU - Lang, Stephanie
AU - Birsoy, Bilge
AU - Wylie, Chris
N1 - Funding Information:
The authors would like to thank Chris Kintner for his generous gift of the NICD and Su(H)-DBM constructs, and for his feedback on this manuscript. The authors would also like to acknowledge the financial support of the Cincinnati Children’s Hospital Research Foundation, and the National Institutes of Health (1R01HD045737).
PY - 2008/3/1
Y1 - 2008/3/1
N2 - Little is known of the control of gene expression in the animal hemisphere of the Xenopus embryo. Here we show that expression of FoxI1e, a gene essential for normal ectoderm formation, is expressed regionally within the animal hemisphere, in a highly dynamic fashion. In situ hybridization shows that FoxI1e is expressed in a wave-like fashion that is initiated on the dorsal side of the animal hemisphere, extends across to the ventral side by the mid-gastrula stage, and is then turned off in the dorsal ectoderm, the neural plate, at the neurula stage. It is confined to the inner layers of cells in the animal cap, and is expressed in a mosaic fashion throughout. We show that this dynamic pattern of expression is controlled by both short- and long-range signals. Notch signaling controls both the mosaic, and dorsal/ventral changes in expression, and is controlled, in turn, by Vg1 signaling from the vegetal mass. FoxI1e expression is also regulated by nodal signaling downstream of VegT. Canonical Wnt signaling contributes only to late changes in the FoxI1e expression pattern. These results provide new insights into the roles of vegetally localized mRNAs in controlling zygotic genes expressed in the animal hemisphere by long-range signaling. They also provide novel insights into the role of Notch signaling at the earliest stages of vertebrate development.
AB - Little is known of the control of gene expression in the animal hemisphere of the Xenopus embryo. Here we show that expression of FoxI1e, a gene essential for normal ectoderm formation, is expressed regionally within the animal hemisphere, in a highly dynamic fashion. In situ hybridization shows that FoxI1e is expressed in a wave-like fashion that is initiated on the dorsal side of the animal hemisphere, extends across to the ventral side by the mid-gastrula stage, and is then turned off in the dorsal ectoderm, the neural plate, at the neurula stage. It is confined to the inner layers of cells in the animal cap, and is expressed in a mosaic fashion throughout. We show that this dynamic pattern of expression is controlled by both short- and long-range signals. Notch signaling controls both the mosaic, and dorsal/ventral changes in expression, and is controlled, in turn, by Vg1 signaling from the vegetal mass. FoxI1e expression is also regulated by nodal signaling downstream of VegT. Canonical Wnt signaling contributes only to late changes in the FoxI1e expression pattern. These results provide new insights into the roles of vegetally localized mRNAs in controlling zygotic genes expressed in the animal hemisphere by long-range signaling. They also provide novel insights into the role of Notch signaling at the earliest stages of vertebrate development.
KW - Animal gene expression
KW - Ectoderm
KW - FoxI1e
KW - Xenopus
UR - http://www.scopus.com/inward/record.url?scp=39549089307&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=39549089307&partnerID=8YFLogxK
U2 - 10.1016/j.ydbio.2007.12.022
DO - 10.1016/j.ydbio.2007.12.022
M3 - Article
C2 - 18234171
AN - SCOPUS:39549089307
SN - 0012-1606
VL - 315
SP - 161
EP - 172
JO - Developmental Biology
JF - Developmental Biology
IS - 1
ER -