Disease relevance of fn1

• Incubation of IHNV with soluble FN2 before addition to cells also increased infection [1].

High impact information on fn1

• Based on these data, we propose that the extra-embryonic YSL regulates myocardial migration, at least in part by influencing fibronectin expression and subsequent assembly of the extracellular matrix in embryonic tissues [2].
• The initiation of somite formation coincides with an increase in the phosphorylation of Fak, and the accumulation of Fak, phosphorylated Fak, paxillin, and fibronectin at nascent somite boundaries [3].
• We observed significant differences in detachment force and work between cultured mesendodermal progenitors from wild-type embryos and from slb/wnt11 mutant embryos, which carry a loss-of-function mutation in the wnt11 gene, when tested on fibronectin-coated substrates [4].
• Here we show that Wnt11, a key signal regulating gastrulation movements, is needed for the adhesion of zebrafish mesendodermal progenitor cells to fibronectin, an abundant extracellular matrix component during gastrulation [4].
• Genomic sequence analysis has revealed that FN2 is generated by an alternative RNA splicing pattern that has not been described for FN in other organisms [5].

Biological context of fn1

• Our data suggest that notch- and integrinalpha5-dependent cell polarization and Fibronectin matrix assembly occur concomitantly and interdependently during border morphogenesis [6].
• In amphibians, birds and mammals, multiple isoforms of fibronectin are generated by differential RNA splicing at three exons [7].
• Their developmentally regulated expression, extracellular location, and affinity for extracellular components (such as laminin and fibronectin) suggest a role in embryonic development, but so far this has not been unequivocally established [8].
• An open reading frame of 2796 base pairs encodes a mature protein consisting of heptad repeats, a cysteine-rich amino terminal region, 3.5 epidermal growth factor-like repeats, five fibronectin type III homologous repeats, and a domain homologous to fibrinogen [9].

Anatomical context of fn1

• Therefore, Integrinalpha5-directed assembly of Fibronectin appears critical for epithelialization and boundary maintenance of somites [10].
• During myocardial migration, Fibronectin is deposited at the midline between the endoderm and endocardial precursors, and laterally around the myocardial precursors [11].
• In the complete absence of Fibronectin, adherens junctions between myocardial precursors do not form properly, suggesting that cell-substratum interactions are required for epithelial organization [11].
• Reverse transcription-polymerase chain reaction analysis and RNase protection assays reveal that FN2 mRNA is present in the zebrafish embryo throughout development as well as in cultures of an established liver cell line [5].
• A new study of zebrafish cardiogenesis published in this issue of Developmental Cell indicates that precursor migration involves formation of a coherent epithelium and that fibronectin plays an important role in maintaining cardiac epithelial integrity [12].

Other interactions of fn1

• Furthermore, with an additional deficiency in ephrin-B2a, the segmental defect in itga5 or fn mutant embryos is expanded posteriorly, indicating that both Integrin-Fibronectin and Eph-Ephrin systems function cooperatively in maintaining somite boundaries [10].

Analytical, diagnostic and therapeutic context of fn1

• Sequence analysis of zebrafish fibronectin (FN) cDNAs indicates that at least two forms of the protein exist in fish [5].
• Incubation of nontransfected cells with soluble recombinant FN2 increased IHNV infection, as measured by plaque assay [1].

References