PUBLICATION

Localized rbp4 expression in the yolk syncytial layer plays a role in yolk cell extension and early liver development

Authors
Li, Z., Korzh, V., and Gong, Z.
ID
ZDB-PUB-071023-20
Date
2007
Source
BMC Developmental Biology   7(1): 117 (Journal)
Registered Authors
Gong, Zhiyuan, Korzh, Vladimir, Li, Zhen
Keywords
none
MeSH Terms
  • Sequence Analysis, DNA
  • Oligonucleotides, Antisense
  • Body Patterning
  • Gene Expression Regulation, Developmental*
  • Liver/embryology*
  • Liver/metabolism
  • Yolk Sac/growth & development
  • Yolk Sac/metabolism*
  • Embryo, Nonmammalian
  • Animals
  • Zebrafish/embryology*
  • Zebrafish/genetics
  • Reverse Transcriptase Polymerase Chain Reaction
  • RNA, Messenger/biosynthesis
  • Retinol-Binding Proteins, Plasma/genetics*
  • Zebrafish Proteins/genetics*
(all 16)
PubMed
17945029 Full text @ BMC Dev. Biol.
Abstract
BACKGROUND: The number of genes characterized in liver development is steadily increasing, but the origin of liver precursor cells and the molecular control of liver formation remain poorly understood. Existing theories about formation of zebrafish visceral organs emphasize either their budding from the endodermal rod or formation of independent anlage followed by their later fusion, but none of these is completely satisfactory in explaining liver organogenesis in zebrafish. RESULTS: Expression of a gene encoding the retinol binding protein 4 (Rbp4) was analyzed in zebrafish. rbp4, which is expressed mainly in the liver in adults, was shown to be expressed in the yolk syncytial layer (YSL) during early embryogenesis. At 12-16 hpf rbp4 expression was restricted to the ventro-lateral YSL and later expanded to cover the posterior YSL. We demonstrated that rbp4 expression was negatively regulated by Nodal and Hedgehog (Hh) signalling and positively controlled by retinoic acid (RA). Knockdown of Rbp4 in the YSL resulted in shortened yolk extension as well as the formation of two liver buds, which could be due to impaired migration of liver progenitor cells. rbp4 appears also to regulate the extracellular matrix protein Fibronectin1 (Fn1) specifically in the ventro-lateral yolk, indicating a role of Fn1 in liver progenitor migration. Since exocrine pancreas, endocrine pancreas, intestine and heart developed normally in Rbp4 morphants, we suggest that rbp4 expression in the YSL is required only for liver development. CONCLUSION: The characteristic expression pattern of rbp4 suggests that the YSL is patterned despite its syncytial nature. YSL-expressed Rbp4 plays a role in formation of both yolk extension and liver bud, the latter may also require migration of liver progenitor cells.
Genes / Markers
Figures
Figure Gallery (5 images)
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Expression
Phenotype
Mutations / Transgenics
Allele Construct Type Affected Genomic Region
ndr2_unspecified
    Unspecified
    shha_unspecified
      Unspecified
      smo_unspecified
        Unspecified
        ta52b
          Point Mutation
          tbx16_unspecified
            Unspecified
            tbxta_unspecified
              Unspecified
              tdgf1_unspecified
                Unspecified
                tfi91
                  Point Mutation
                  zf5TgTransgenic Insertion
                    1 - 9 of 9
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                    Human Disease / Model
                    No data available
                    Sequence Targeting Reagents
                    Target Reagent Reagent Type
                    rbp4MO1-rbp4MRPHLNO
                    rbp4MO2-rbp4MRPHLNO
                    1 - 2 of 2
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                    Fish
                    Antibodies
                    No data available
                    Orthology
                    No data available
                    Engineered Foreign Genes
                    Marker Marker Type Name
                    GFPEFGGFP
                    1 - 1 of 1
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                    Mapping
                    No data available