title: High mobility group B proteins regulate mesoderm formation and dorsoventral patterning during zebrafish and Xenopus early development.
abstract: The high mobility group (HMG) proteins constitute a superfamily of nuclear proteins that regulate the expression of a wide range of genes through architectural remodeling of the chromatin structure, and the formation of multiple protein complexes on promoter/enhancer regions, but their function in germ layer specification during early development is not clear. Here we show that hmgb genes regulate mesoderm formation and dorsoventral patterning both in zebrafish and Xenopus early embryos. Overexpression of hmgb3 blocks the expression of the pan-mesoderm gene no tail/Xbra and other ventrolateral mesoderm genes, and results in embryos with shortened anteroposterior axis, while overexpression of hmgb3EnR, which contains the engrailed repressor domain, most potently repressed no tail expression and mesoderm formation. However, hmgb3VP16, which contains the transcriptional activation domain of VP16, had an opposite effect, indicating that hmgb3 may function as a repressor during mesoderm induction and patterning. In addition, we show that hmgb3 inhibits target gene expression downstream of mesoderm-inducing factors. Furthermore, using reporter gene assays in Xenopus whole embryos, we show that hmgb3 differentially regulates the activation of various mesendoderm reporter genes. In particular, it up-regulates the goosecoid, but inhibits the Xbra reporter gene activation. Therefore, our results suggest that hmgb genes may function to fine-tune the specification and/or dorsoventral patterning of mesoderm during zebrafish and Xenopus development.
authors: School of Life Sciences, Shandong University, 27 Shanda Nan Road, Jinan 250100, China.
authors: Jian-Meng
authors: JM
authors: Cao
authors: Shang-Qi
authors: SQ
authors: Li
authors: Hong-Wei
authors: HW
authors: Zhang
authors: De-Li
authors: DL
authors: Shi
mesh_terms: D000818:Animals; D019521:Body Patterning / Q000235:genetics / Q000502:physiology*; D005326:Fetal Proteins; D018507:Gene Expression Regulation, Developmental; D051956:Goosecoid Protein / Q000235:genetics / Q000378:metabolism; D024002:HMGB Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D025765:HMGB3 Protein / Q000235:genetics / Q000378:metabolism; D008648:Mesoderm / Q000254:growth & development / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D020825:T-Box Domain Proteins / Q000235:genetics / Q000378:metabolism; D015533:Transcriptional Activation / Q000235:genetics; D015854:Up-Regulation; D014981:Xenopus / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D029867:Xenopus Proteins / Q000235:genetics / Q000378:metabolism; D015027:Zebrafish / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D029961:Zebrafish Proteins / Q000235:genetics / Q000378:metabolism; D000098908:Brachyury Protein
chemical_list: D005326:Fetal Proteins; D051956:Goosecoid Protein; D024002:HMGB Proteins; D025765:HMGB3 Protein; D012097:Repressor Proteins; D020825:T-Box Domain Proteins; D029867:Xenopus Proteins; D029961:Zebrafish Proteins; D000098908:Brachyury Protein; C116765:TBXT protein, Xenopus