Abstract
Signaling mechanisms underlying the induction of the pre-pancreatic tissue within the endoderm remain poorly understood. Through an expression cloning strategy, we have identified a previously uncharacterized pancreatic factor that we named Shirin. Interestingly, the non-coding RNA regulatory sequence (3 UTR) of Shirin is sufficient to induce insulin expression in Xenopus embryos. Biochemical studies demonstrate that this RNA sequence is able to bind directly to a trans-acting factor, Vg1RBP, which was previously shown to be involved in the localization of endodermal determinant factors. Loss-of-function analysis indicates that Vg1RBP is required for establishment of pancreatic fate within the endoderm, suggesting a synergism between Vg1RBP and Shirin in the embryo. This study argues for a central role of post-transcriptional mechanisms in establishing pancreatic fate, where a 3 UTR may recruit factors necessary for pancreatic development, and highlights an unknown embryological activity of Vg1RBP.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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3' Untranslated Regions
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Animals
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Base Sequence
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Biomarkers / analysis
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Blotting, Western
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Cross-Linking Reagents / pharmacology
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DNA, Complementary / chemistry
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Embryo, Nonmammalian
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GTPase-Activating Proteins / chemistry
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GTPase-Activating Proteins / genetics
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Glycoproteins / genetics
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Glycoproteins / physiology*
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In Situ Hybridization
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Insulin / metabolism
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Models, Biological
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Molecular Sequence Data
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Oligonucleotides, Antisense / pharmacology
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Pancreas / embryology*
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Point Mutation
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Precipitin Tests
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RNA-Binding Proteins / physiology*
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Reverse Transcriptase Polymerase Chain Reaction
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Transforming Growth Factor beta / genetics
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Transforming Growth Factor beta / physiology*
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Xenopus / embryology
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Xenopus Proteins / chemistry
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Xenopus Proteins / genetics
Substances
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3' Untranslated Regions
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Biomarkers
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Cross-Linking Reagents
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DNA, Complementary
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GDF1 protein, Xenopus
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GTPase-Activating Proteins
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Glycoproteins
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Insulin
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Oligonucleotides, Antisense
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RNA-Binding Proteins
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Transforming Growth Factor beta
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Xenopus Proteins
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shirin protein, Xenopus