Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
2006-5-16
pubmed:abstractText
Somitogenesis is the key developmental step, which divides the vertebrate body axis into segmentally repeated structures. It requires an intricate process of pre-patterning, which is driven by an oscillator mechanism consisting of the Delta-Notch pathway and various hairy- and Enhancer of split-related (her) genes. The subset of her genes, which are necessary to set up the segmentation clock, reveal a complex scenario of interactions. To understand which her genes are essential core players in this process, we compared the expression patterns of somitogenesis-relevant her genes in zebrafish and medaka (Oryzias latipes). Most of the respective medaka genes (Ol-her) are duplicated like what has been shown for zebrafish (Dr-her) and pufferfish genes (Fr-her). However, zebrafish genes show some additional copies and significant differences in expression patterns. For the paralogues Dr-her1 and Dr-her11, only one copy exists in the medaka (Ol-her1/11), which combines the expression patterns found for both zebrafish genes. In contrast to Dr-her5, the medaka orthologue appears to play a role in somitogenesis because it is expressed in the presomitic mesoderm (PSM). PSM expression also suggests a role for both Ol-her13 genes, homologues of mouse Hes6 (mHes6), in this process, which would be consistent with a conserved mHes6 homologue gear in the segmentation clock exclusively in lower vertebrates. Members of the mHes5 homologue group seem to be involved in somite formation in all vertebrates (e.g. Dr- and Ol-her12), although different paralogues are additionally recruited in zebrafish (e.g. Dr-her15) and medaka (e.g. Ol-her4). We found that the linkage between duplicates is strongly conserved between pufferfish and medaka and less well conserved in zebrafish. Nevertheless, linkage and orientation of several her duplicates are identical in all three species. Therefore, small-scale duplications must have happened before whole genome duplication occurred in a fish ancestor. Expression of multiple stripes in the intermediate PSM, characteristic for the zebrafish orthologues, is absent in all somitogenesis-related her genes of the medaka. In fact, the expression mode of Ol-her1/11 and Ol-her5 indicates dynamism similar to the hairy clock genes in chicken and mouse. This suggests that Danio rerio shows a rather derived clock mode when compared to other fish species and amniotes or that, alternatively, the clock mode evolved independently in zebrafish, medaka and mouse or chicken.
pubmed:commentsCorrections
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0949-944X
pubmed:author
pubmed:issnType
Print
pubmed:volume
216
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
315-32
pubmed:dateRevised
2010-11-18
pubmed:meshHeading
pubmed-meshheading:16544152-Amino Acid Sequence, pubmed-meshheading:16544152-Animals, pubmed-meshheading:16544152-Basic Helix-Loop-Helix Transcription Factors, pubmed-meshheading:16544152-Biological Clocks, pubmed-meshheading:16544152-Chick Embryo, pubmed-meshheading:16544152-Conserved Sequence, pubmed-meshheading:16544152-Embryonic Development, pubmed-meshheading:16544152-Gene Dosage, pubmed-meshheading:16544152-Gene Expression Regulation, Developmental, pubmed-meshheading:16544152-Genetic Linkage, pubmed-meshheading:16544152-Mice, pubmed-meshheading:16544152-Molecular Sequence Data, pubmed-meshheading:16544152-Morphogenesis, pubmed-meshheading:16544152-Oryzias, pubmed-meshheading:16544152-Phylogeny, pubmed-meshheading:16544152-Physical Chromosome Mapping, pubmed-meshheading:16544152-Sequence Homology, Amino Acid, pubmed-meshheading:16544152-Somites, pubmed-meshheading:16544152-Species Specificity
pubmed:year
2006
pubmed:articleTitle
Comparative analysis of her genes during fish somitogenesis suggests a mouse/chick-like mode of oscillation in medaka.
pubmed:affiliation
Universität zu Köln, Institut für Genetik [corrected] Zülpicher Str., 47, 50674 Köln, Germany. martin.gajewski@uni-koeln.de
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't