Dissertation > Excellent graduate degree dissertation topics show

A Maternal Transcription Factor Controls the Paraxial Mesoderm Patterning in Zebrafish

Author: HeYing
Tutor: LuoZuo
School: Zhejiang University
Course: Developmental Biology
Keywords: zebrafish embryo development Axial-paraxial mesoderm patterning Maternal control Vsx1 control mechanism
CLC: Q954.4
Type: PhD thesis
Year: 2013
Downloads: 48
Quote: 0
Read: Download Dissertation


Axial-paraxial mesoderm patterning is a special dorsal-ventral (DV) patterning event of vertebrates, However, the identified DV patterning mechanisms could not explain the initiation of axial-paraxial mesoderm patterning. In zebrafish, spt cell-autonomously regulates paraxial mesoderm specification and flh represses spt expression to promote axial mesoderm fate, but the expression domains of spt and flh initially overlap in the entire margin zone of the embryo. Defining flh and spt territories is therefore a premise of axial-paraxial patterning. Our revious studies have shown that a transcriptional factor Vsxl directly represses axial mesoderm gene flh transcription to preserve paraxial mesoderm gene spt expression in zebrafish. The present investigations further revealed the function and molecular mechanisn of Vsxl in regulating axial-paraxial mesoderm patterning, as well as the roles of different Vsxl domains. The main results and conclusions are as follows:1. Whole mount in situ immunohistochemistry analysis showed that maternal vsxl mRNA directs Vsxl translation in the ventrolaternal region during cleavage.2. By injection of vsxl tbMO, which can blocking the translation of vsxl mRNA, and vsxl sbMO, which can interfere with the splicing of newly synthesized zygotic vsxl mRNA but leave the maternal vsx1mRNA intact, we determine that maternal Vsxl acts as a ventralizing factor essential for paraxial mesoderm domain patterning at blastula stage.3. Maternal Vsxl promotes paraxial mesoderm specification in the ventrolateral margin via direct transcriptional represson of flh to preserve spt expression.4. Maternal Vsxl regulate the maintenance of axial-paraxial mesoderm patterning. This function is independent of Wnt8and Bmp2b signaling pathways. It seems that there are two parallel mechanisms co-regulating the maintenance of axial-paraxial mesederm patterning.5. We created a transcriptional fusion construct En-Vsxl by replacing the N-terminal125amino acids of Vsxl with Engrailed repressing domain and a transcriptional activator fusion construct VP16-Vsxl with the VP16activating domain. By analyzing the phenotypes and flh expression of the En-vsxl or VP16-vsxl mRNA injected embryos, we demonstrated that the function of N-terminal region of Vsxl is similar to the Engrailed repressor domain and Vsxl acts as a transcriptional repressor.6. The sole binding site for mediating Vsxl repressing flh at the proximal promoter of flh was identified by analyzing the mutation of consensus sequences at the binding site detected by CHIP.7. The sequence characteristics of Vsxl-specific binding site at Vsxl target genes was determined by comparing the up-and down-stream sequences of potential binding sites of flh proximal promoters. Mutation analysis revealed that, except the consensus sequences TAATTG, at last a CCC motif is essential for Vsxl-DNA reciprocal recognition and binding, and the CVC domain might be involved in Vsx1-DNA binding.These results provide an evidence for the first time that materal Vsxl controls paraxial mesoderm patterning via direct transcriptional repression in vertebrates. Therefore, zygotic signaling gradients generated after DV axis formation is unlikely the principal regulatory component of primary axial-paraxial patterning. The sequence characteristics of Vxsl binding site and the function CVC domain will be usful for revealing the roles of paired-like homeobox genes.

Related Dissertations

  1. Study on the Fine Structure of Intestine and Intestinal Mucosal Barrier in Zebrfish (Brachydanio Rerio),Q95-33
  2. An Experimental Study about the Effects of Ginkgolide B on Anti-embryo Implantation,R285.5
  3. The Joint Toxicity Evaluation of Chiral Organophosphrus Pesticides Enantiomers,X174
  4. The Study of Two Phenolic Organic Oxidated by Ozone and the Acute Toxicity,X703
  5. The Establishment of Zebrafish Toxicity Microplate Model and Its Application in Secreening and Evaluation of Marine Natural Products,R285
  6. Study on Mechanisms of Genistein on Vitellogenin Induction in Zebra Fish (Danio Rerio) Hepatocyte,S917.4
  7. The Function of Two Chloroplast-targeted Proteins-FtsHL3 and FtsHL5 in Embryogenesis in Arabidopsis,Q944.4
  8. High-throughput screening in vivo inhibition of macrophage migration in zebrafish Chinese medicine,R285.5
  9. Induction of IGF Binding Protein-6 in Vascular Endothelial Cells is a Conserved Negative Feedback Mechanism in Hypoxia-induced Angiogenesis,Q46
  10. Screening Proteins Interacting with GATA-5 and Functional Research of miR-142-3p in Haematopoiesis,Q78
  11. Study of Combination Effects of Environmental Estrogens and Antiestrogens on Zebrafish (Danio Rerio) Embryos,X174
  12. Craniofacial Abnormalities in Zebrafish Induced by Clomiphene Sodium Citrate,R114
  13. A Research into the Money Laundering and Anti-Money Laundering Institution of Insurance Industry in China,F832
  14. Coagulation factor Ⅲ b in zebrafish embryonic development role,Q954.4
  15. Using Zebrafish as a Model to Study the Effect of Deguelin on COX/PGE2 Signaling Pathway,R285.5
  16. The Study on the Legal Issues of Chinese Enterprises’ Listing in America,F279.2
  17. Functional Analysis of PKB/Akt in Zebrafish Early Developmental Stages,Q55
  18. Craniofacial Dysplasia in Zebrafish Induced by Dexamethasone Sodium Phosphate,X174
  19. A Tentative Study of the Characterization of Development and Differentiation at the Early Life Stages of the Cynoglossus Semilaevis,S917.4
  20. 1.The Function of Vsx1 during Embryogenesis of Goldfish 2.The Construction and Searches of Differentially Expressed Protein Database,Q954.4
  21. Studies on the Toxicity of HgCl2 to Aquatic Organism,X503.2

CLC: > Biological Sciences > Zoology > Animal morphology > Animal Embryology ( of animals,animal viviparous learn )
© 2012 www.DissertationTopic.Net  Mobile