|
Dally (division abnormally delayed) is the name of a gene that encodes a HS-modified-protein found in the fruit fly (''Drosophila melanogaster''). The protein has to be processed after being codified, and in its mature form it is composed by 626 amino acids,〔(Uniprot KB ),〕 forming a proteoglycan rich in heparin sulfate which is anchored to the cell surface via covalent linkage to glycophosphatidylinositol (GPI), so we can define it as a glypican. For its normal biosynthesis it requires sugarless (''sgl''), a gene that encodes an enzyme which plays a critical role in the process of modification of dally. ==Dally’s function== Dally works as a co-receptor of some secreted signaling molecules as fibroblast growth factor, vascular endothelial growth factor, hepatocyte growth factor and members of the Wnt signaling pathway, TGF-b and Hedgehog families. It is also necessary for the cell division patterning during the post-embryonic development of the nervous system. It is a regulatory component of the Wg receptor and is part of a multiprotein complex together with Frizzled (Fz) transmembrane proteins. Therefore it regulates two cell growth factors in Drosophila melanogaster, Wingless (Wg) and Decapentaplegic (Dpp). It must be said that in vertebrates the equivalent to Dpp are Bone Morphogenetic Proteins, and the mammalian equal to Wg might be integrin-beta 4. The first one (Wg) controls cell proliferation and differentiation during embryos development, specifically in epidermis, whereas the latter (Dpp) plays a role in the imaginal discs’ growth. Dpp and Wg are mutually antagonistic in patterning genitalia. Concretely, dally selectively regulates both Wg signalling in epidermis and Dpp in genitalia. This selectivity is supposed to be controlled by the type of Glycosaminoglycan GAG bonded to the dally protein, considering that there is a huge structural variety in GAGs. Tissue malformations occur in various situations. As said in the introduction, the ''sgl'' enzyme is essential for a normal biosynthesis of dally. That is why the absence or malfunction of this enzyme doesn’t allow the correct Wg and Dpp signalling. Also the expression of mutated dally proteins alters Wnt signalling pathways, which leads to anomalies in Drosophila melanogaster’s eye, antennal, genital, wing and neural morphogenesis. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Dally (gene)」の詳細全文を読む スポンサード リンク
|