An SP1-like transcription factor Spr2 acts downstream of Fgf signaling to mediate mesoderm induction.
Fgf signaling, mediated in part by the transcription factor Brachyury/Xbra/Ntl, plays important roles in mesoderm formation during the early development of vertebrate embryos. We have identified a zebrafish gene, spr2, which encodes a member of the Sp1-like transcription factor family. spr2 is expressed in both hypoblast and epiblast cells during late blastulation/early gastrulation, and in some mesodermal and neural tissues at later stages. Injection with spr2 mRNA enhances ntl expression and alleviates the inhibitory effect on ntl of XFD, a Xenopus dominant-negative FGF receptor. In contrast, morpholino- mediated knockdown of Spr2 activity inhibits ntl expression and reduces the inductive effect of Fgfs on ntl. We also demonstrate that Fgf signaling relays mesoderm induction activity of Nodal signaling and Spr2 is involved in this signal relay process. Furthermore, the correct spatial expression of spr2 requires Nodal, Fgf and Wnt signals. We suggest that expression of spr2 is an immediate-early response to mesoderm induction by Fgfs, which in turn regulates the expression of effector genes involved in the development of mesodermal tissues.
Zhao
Jue
J
Department of Biological Sciences and Biotechnology, Protein Sciences Laboratory of the MOE, Tsinghua University, Beijing 100084, China.
Cao
Ying
Y
Zhao
Chengtian
C
Postlethwait
John
J
Meng
Anming
A
D000818:Animals; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D004627:Embryonic Induction / Q000502:physiology*; D005326:Fetal Proteins; D005346:Fibroblast Growth Factors / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental / Q000502:physiology; D008648:Mesoderm / Q000378:metabolism*; D055457:Nodal Protein; D010802:Phylogeny; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051703:Sp Transcription Factors / Q000235:genetics / Q000378:metabolism*; D051705:Sp3 Transcription Factor; D020825:T-Box Domain Proteins / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000235:genetics / Q000378:metabolism; D051153:Wnt Proteins; D015027:Zebrafish / Q000196:embryology; D029961:Zebrafish Proteins / Q000235:genetics / Q000378:metabolism*; D000098908:Brachyury Protein
D004268:DNA-Binding Proteins; D005326:Fetal Proteins; D005346:Fibroblast Growth Factors; D055457:Nodal Protein; D011518:Proto-Oncogene Proteins; D051703:Sp Transcription Factors; D051705:Sp3 Transcription Factor; D020825:T-Box Domain Proteins; D016212:Transforming Growth Factor beta; D051153:Wnt Proteins; D029961:Zebrafish Proteins; D000098908:Brachyury Protein; C516064:Sp5l protein, zebrafish; C094522:wnt8b protein, zebrafish