Outer segment disc membrane assembly in the absence of the pigment epithelium: the effect of exogenous sugars.
When retinal rudiments of Xenopus laevis embryos are allowed to differentiate in vitro, membrane precursors destined for the outer segment do not form well-ordered stacks of membrane leaflets if the pigment epithelium is removed from the outer retinal surface. However, addition of certain saccharides permits the organization of outer segment membranes into stacked membranous saccules, much like that demonstrated during in vivo or in vitro development in the presence of an investing pigment epithelium. Sugars that support the formation of well-organized photoreceptor outer segments include lactose, galactose and their derivatives, while numerous other carbohydrates failed to support outer segment organization.
Cullen Eye Institute, Baylor College of Medicine, Houston, TX 77030.
M M
MM
Stiemke
J G
JG
Hollyfield
D000818:Animals; D002241:Carbohydrates / Q000494:pharmacology*; D002462:Cell Membrane / Q000187:drug effects / Q000502:physiology*; D003470:Culture Media; D004625:Embryo, Nonmammalian; D009414:Nerve Growth Factors / Q000502:physiology*; D010786:Photoreceptor Cells / Q000187:drug effects / Q000502:physiology; D010857:Pigment Epithelium of Eye / Q000502:physiology*; D014982:Xenopus laevis
D002241:Carbohydrates; D003470:Culture Media; D009414:Nerve Growth Factors; C071951:neurotrophin 5; C073922:neurotrophin 4