page 1117, Bashaw et al. describe the activity of a new Rho guanine nucleotide exchange factor in Drosophila melanogaster, GEF64C, that can stimulate axon attraction.
The authors started with flies expressing a chimeric receptor, which caused excessive crossing of the midline of the central nervous system. Overexpression of GEF64C exacerbated this phenotype. Bashaw et al. knew that the established attractants and repellents emanate from the midline, so they interpreted the new phenotye as resulting from increased attraction to the midline. GEF64C overexpression also promoted midline crossing in a mutant that otherwise shows excessive repulsion away from the midline.
The GEF64C effects were diminished by a dominant-negative RhoA, but unaffected by dominant-negative Rac1 or Cdc42. It is unclear how RhoA might promote attraction. But, based on the convergence of multiple guidance signals downstream of receptors, this type of downstream machinery presents an intriguing possibility for therapies that aim to stimulate axon regrowth in injured humans. ▪
1117: Bashaw et al. Kwa mfano, kuna uwezekano wa kuwa na Rho-guanine nucleotide exchange factor (RGUNF64C) katika Drosophila melanogaster, ambayo inaweza kuchochea kuvutia kwa axon. Kwa mfano, ndege wanaosababisha kimeriki receptor, ambayo ni muhimu kwa ajili ya kuhamisha ya katikati ya mfumo wa neva. Ufafanuzi wa GEF64C ulizidisha hali hii ya phenotype. Bashaw et al. Kwa kuwa watu walifahamu kwamba vitu vinavyovutia na vinavyovutia hutoka kwenye mstari wa kati, walitafsiri kwamba kitu hicho kipya kilitokana na kuongezeka kwa mvuto kuelekea mstari wa kati. GEF64C overexpression pia iliongeza kuvuka kwa mstari wa kati katika mutant ambayo kwa njia nyingine inaonyesha repulsion kupita kiasi mbali na mstari wa kati. Madhara ya GEF64C yalipunguzwa na RhoA ya msingi, lakini haikuathiriwa na Rac1 au CdC ya msingi. Haijulikani wazi jinsi RhoA inaweza kukuza kuvutia. Lakini, kulingana na kuunganishwa kwa ishara nyingi za mwongozo chini ya receptors, aina hii ya mashine ya chini ya mto inatoa uwezekano wa kuvutia kwa matibabu ambayo yana lengo la kuchochea axon regrowth katika wanadamu waliojeruhiwa. ▪ Ni nini?