Fibronectin mediates correct positioning of the interrenal organ in zebrafish.
BACKGROUND
Fibronectin (Fn) forms a centripetal gradient during the fetal adrenal gland organogenesis, and modulates hormone responsiveness of adrenocortical cells in the primary culture. However, how Fn is involved in organ formation of the adrenal gland remains unclear.


RESULTS
In this study, we found that Fn accumulates around migrating ff1b-expressing interrenal cells, which were marked by the ff1b promoter-driven transgenic fluorescence, during the course of interrenal organ assembly. The interrenal cells displaying the migratory phenotype were absent in the fn1 mutant, while specification and kidney association of the interrenal tissue remained normal. The Fn deposition in the interrenal microenvironment was severely reduced in the vessel-deficient ets1b morphant, implying its origin of synthesis from the peri-interrenal vasculature. In the fn1 mutant, early-migrating chromaffin cells were capable of interacting with steroidogenic interrenal cells, yet continuous migration and midline convergence of chromaffin cells were disrupted. Migration defects of both interrenal and chromaffin lineages, in the absence of Fn, thus led to incomplete interrenal organ assembly in aberrant positions.


CONCLUSIONS
Our results indicate that Fn is essential for patterning interrenal organ formation, by modulating the migratory behavior of both steroidogenic interrenal and chromaffin cells.
Department of Life Science, Tunghai University, Taichung, Taiwan, R.O.C.
Chih-Wei
CW
Chou
Chih-Hao
CH
Chiu
Yi-Wen
YW
Liu
D015096:3-Hydroxysteroid Dehydrogenases / Q000235:genetics / Q000378:metabolism; D000818:Animals; D030801:Animals, Genetically Modified; D019521:Body Patterning / Q000235:genetics*; D002465:Cell Movement / Q000235:genetics; D019439:Chromaffin Cells / Q000378:metabolism / Q000502:physiology; D004625:Embryo, Nonmammalian; D005353:Fibronectins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D018507:Gene Expression Regulation, Developmental; D015971:Gene Expression Regulation, Enzymologic; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D007401:Interrenal Gland / Q000196:embryology* / Q000378:metabolism; D038081:Organogenesis / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D015027:Zebrafish / Q000196:embryology* / Q000235:genetics / Q000378:metabolism; D029961:Zebrafish Proteins / Q000235:genetics / Q000378:metabolism
D005353:Fibronectins; D014157:Transcription Factors; D029961:Zebrafish Proteins; C478921:nr5a1a protein, zebrafish; D049452:Green Fluorescent Proteins; D015096:3-Hydroxysteroid Dehydrogenases