Microarray-based identification of VegT targets in Xenopus.
The Xenopus T box family member VegT is expressed maternally in the vegetal hemisphere of the embryo. Mis-expression of VegT in prospective ectodermal tissue causes ectopic activation of mesodermal and endodermal markers, and ablation of VegT transcripts prevents proper formation of the mesendoderm, with the entire embryo developing as epidermis. These observations define VegT as a key initiator of mesendodermal development in the Xenopus embryo, and in an effort to understand how it exerts its effects we have used microarray analysis to compare gene expression in control animal caps with that in ectodermal tissue expressing an activated form of VegT. This procedure allowed the identification of 99 potential VegT targets, and we went on to study the expression patterns of these genes and then to ask, for those that are expressed in mesoderm or endoderm, which are direct targets of VegT. The putative regulatory regions of the resulting 14 genes were examined for T domain binding sites, and we also asked whether their expression is down-regulated in embryos in which VegT RNA is ablated. Finally, the functions of these genes were assayed by both over-expression and by use of antisense morpholino oligonucleotides. Our results provide new insights into the function of VegT during early Xenopus development.
Taverner
Nicola V
NV
Department of Zoology, Wellcome Trust/Cancer Research UK Gurdon Institute, University of Cambridge, Henry Wellcome Building of Cancer and Developmental Biology, Tennis Court Road, Cambridge CB2 1QN, UK.
Kofron
Matt
M
Shin
Yongchol
Y
Kabitschke
Christin
C
Gilchrist
Michael J
MJ
Wylie
Chris
C
Cho
Ken W Y
KW
Heasman
Janet
J
Smith
J C
JC
D000818:Animals; D001665:Binding Sites; D018076:DNA, Complementary / Q000378:metabolism; D015536:Down-Regulation; D004707:Endoderm / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D005821:Genetic Techniques; D016678:Genome; D017403:In Situ Hybridization; D008648:Mesoderm / Q000378:metabolism; D046228:Microarray Analysis / Q000379:methods*; D008957:Models, Genetic; D009693:Nucleic Acid Hybridization; D020411:Oligonucleotide Array Sequence Analysis; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D012313:RNA / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D020825:T-Box Domain Proteins / Q000378:metabolism*; D015854:Up-Regulation; D014981:Xenopus / Q000235:genetics*; D029867:Xenopus Proteins / Q000235:genetics / Q000378:metabolism*
D018076:DNA, Complementary; D012333:RNA, Messenger; D020825:T-Box Domain Proteins; C103966:VegT protein, Xenopus; D029867:Xenopus Proteins; D012313:RNA