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ABSTRACT: In the present study, a zebrafish hsp27 promoter was isolated and used to develop heat shock inducible gfp transgenic zebrafish. The endogenous hsp27 mRNAs were constitutively expressed from 4 hpf and increased in several regions of brain, heart and somites in early embryogenesis until 24 hpf. Subsequently, the expression was reduced significantly but maintained in the heart and ears. Heat shock induced hsp27 mRNAs in the blastoderm from 6 hpf and later in somites, branchial arches and several regions of brain. Similarly in hsp27-gfp transgenic zebrafish, constitutive GFP expression was observed from 11 hpf. GFP expression was mainly in the skin cells and increased to the peak level at 7 dpf, followed by a reduction. The constitutive GFP expression in the heart was initiated from 50 hpf and maintained even in the adult fish. After heat shock, GFP expression was mainly induced in the muscle in addition to a mild increase in the skin and heart. The early stages of the embryos were more sensitive than late stages as the time required for induced GFP expression in the muscle is shorter. Thus, the hsp27-gfp transgenic line generally recapitulates the expression pattern and heat shock inducibility of endogenous hsp27 RNAs. We also tested the potential of using the hsp27-gfp transgenic zebrafish embryos for heavy metal induction and demonstrated the inducibility of GFP expression by arsenic; this pattern of induction was also supported by examination of endogenous hsp27 mRNA.
Gene 02/2008; 408(1-2):85-94. · 2.34 Impact Factor
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ABSTRACT: In contrast to what we know on development of endocrine pancreas, the formation of exocrine pancreas remains poorly understood. To create an animal model that allows observation of exocrine cell differentiation, proliferation, and morphogenesis in living animals, we used the zebrafish elastaseA (elaA) regulatory sequence to develop transgenic zebrafish that display highly specific exocrine pancreas expression of GFP in both larvae and adult. By following GFP expression, we found that the pancreas in early development was a relatively compact organ and later extended posterior along the intestine. By transferring the elaA:gfp transgene into slow muscle omitted mutant that is deficient in receiving Hedgehog signals, we further showed that Hedgehog signaling is required for exocrine morphogenesis but not for cell differentiation. We also applied the morpholino knockdown and toxin-mediated cell ablation approaches to this transgenic line. We showed that the development of exocrine pancreas is Islet-1 dependent. Injection of the diphtheria toxin A (DTA) construct under the elastaseA promoter resulted in selective ablation of exocrine cells while the endocrine cells and other endodermal derivatives (liver and intestine) were not affected. Thus, our works demonstrated the new transgenic line provided a useful experimental tool in analyzing exocrine pancreas development.
Experimental Cell Research 06/2006; 312(9):1526-39. · 3.58 Impact Factor
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ABSTRACT: In the present work, three zebrafish cDNA clones encoding transferrin, intestinal fatty acid binding protein (IFABP), and elastaseB were cloned and their expression patterns in early zebrafish development were characterized as differentiation markers for the three major endoderm organs: liver, intestine, and exocrine pancreas. transferrin and ifabp mRNAs exhibit a biphasic expression pattern during early development. transferrin mRNAs were first expressed at approximately 7 hours postfertilization (hpf) in the yolk syncytial layer (YSL) and later in the liver rudiment (from approximately 48 hpf) and in the esophagus transiently (72-96 hpf). Ifabp mRNAs were initially expressed in the YSL at the ventral side during late epiboly (8-9 hpf), spread throughout the YSL of later stage embryos, and appeared in the intestine rudiment at approximately 36 hpf. In contrast to the transferrin and ifabp mRNAs, elastaseB mRNAs were not expressed in the yolk sac or YSL, and these transcripts were detected exclusively in the exocrine pancreas after approximately 56 hpf.
Developmental Dynamics 06/2004; 230(1):165-73. · 2.54 Impact Factor
