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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
2005-3-30
pubmed:abstractText
Many details of cardiac chamber morphogenesis could be revealed if muscle fiber development could be visualized directly within the hearts of living vertebrate embryos. To achieve this end, we have used the active promoter of the MLC1v gene to drive expression of green fluorescent protein (GFP) in the developing tadpole heart. By using a line of Xenopus laevis frogs transgenic for the MLC1v-EGFP reporter, we have observed regionalized patterns of muscle formation within the ventricular chamber and maturation of the atrial chambers, from the onset of chamber formation through to the adult frog. In f1 generation MLC1v-EGFP animals, promoter activity is first detected within the looping heart tube and delineates the forming ventricular chamber and proximal outflow tract throughout their development. The 8-kb MLC1v promoter faithfully reproduces the embryonic expression of the endogenous MLC1v mRNA. At later larval stages, weak patches of EGFP fluorescence are found on the atrial side of the atrioventricular boundary. Subsequently, an extensive lattice of MLC1v-expressing fibers extend across the mature atrial chambers of adult frog hearts and the transgene reveals the differing arrangement of muscle fibers in chamber versus outflow myocardium. The complete activity of the promoter resides within the proximal 4.5 kb of the MLC1v DNA fragment, whereas key elements regulating chamber-specific expression are present in the proximal-most 1.5 kb. Finally, we demonstrate how cardiac and craniofacial muscle expression of the MLC1v promoter can be used to diagnose mutant phenotypes in living embryos, using the injection of RNA encoding a Tbx1-engrailed repressor-fusion protein as an example.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
1058-8388
pubmed:author
pubmed:copyrightInfo
Copyright 2005 Wiley-Liss, Inc.
pubmed:issnType
Print
pubmed:volume
232
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1003-12
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2005
pubmed:articleTitle
The MLC1v gene provides a transgenic marker of myocardium formation within developing chambers of the Xenopus heart.
pubmed:affiliation
Division of Developmental Biology, National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, United Kingdom.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't