Carotenoid replacement therapy in Drosophila: Recovery of membrane, opsin and visual pigment

Sapp, Randall; Christianson, J. Scott; Maier, Linnette; Studer, Kent; Stark, William S.

doi:10.1016/0014-4835(91)90147-7

Cited by 26 publications

(36 citation statements)

References 17 publications

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“…On the other hand, the Asn to Ile mutation in rab6 increased secretion rate (7). The lack of a mutant phenotype in our studies does not result from Rab6 N125I (33,44), ninaA (35), ninaC (45,46), as well as vitamin A deprived flies (47). All these flies possess reduced rhodopsin content, suggesting that the reduced size of the rhabdomere in the Drab6 Q71L mutant is likely the result of poor rhodopsin maturation.…”

Section: Drab6mentioning

confidence: 60%

Rab6 Regulation of Rhodopsin Transport inDrosophila

Shetty¹,

Kurada²,

O'Tousa

1998

Journal of Biological Chemistry

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Rab6 is a GTPQ71L is a GTPase defective mutant, indicating that anterograde transport of rhodopsin requires Rab6 GTPase function. The three Drab6 strains had no effect on the expression of several other photoreceptor proteins. The Drab6 Q71L photoreceptors show marked histological defects at young ages and degenerate over a two week time span. These results establish that rhodopsin is transported via a Rab6 regulated pathway and that defects in trafficking pathways lead to retinal degeneration.

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Section: Drab6mentioning

confidence: 60%

Rab6 Regulation of Rhodopsin Transport inDrosophila

Shetty¹,

Kurada²,

O'Tousa

1998

Journal of Biological Chemistry

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“…In Drosophila, opsin is reduced to 1% of normal levels (Ozaki et al, 1993). Visual pigment is restored in mature insect photoreceptors when they are provided with chromophore Bennett & White, 1991;Sapp et al, 1991a;Chen & Stark, 1992). Although the conditions of chromophore depletion and recovery are certainly non-physiological, they provide opportunities for experiments on the possible roles played by the chromophore in regulating synthesis, turnover, maturation and deployment of visual pigment.…”

Section: Discussionmentioning

confidence: 94%

“…Thus it is not surprising that rhodopsin levels are reduced in insects suffering from vitamin A deficiency (Goldsmith et al, 1964;Brammer & White, 1969;Boschek & Hamdorf, 1976;Harris et al, 1977;Huber et al, 1990). More interesting is the observation that the apoprotein, opsin, is also severely reduced in insect photoreceptors by chromophore depletion (Paulsen & Schwemer, 1983;deCouet & Tanimura, 1987;Sapp et al, 1991a;Huber et al, 1994). In Drosophila, opsin is reduced to 1% of normal levels (Ozaki et al, 1993).…”

Section: Discussionmentioning

confidence: 96%

“…Other studies suggest that insects recover visual function as levels of opsin and rhodopsin rise (e.g. Paulsen & Schwemer, 1983;Bennett & White, 1991;Sapp et al, 1991a). Results from experiments with Drosophila (Sun et al, 1993) and Calliphora (Schwemer & Spengler, 1992) have led to the tantalizing suggestion that retinoids may control opsin gene transcription in insects.…”

Section: Introductionmentioning

confidence: 94%

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Carotenoid replacement inDrosophila: freeze-fracture electron microscopy

Stark

White

1996

J Neurocytol

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Because of the consequent lack of photopigment chromophore, carotenoid/ retinoid (vitamin A) deprivation during the larval period of Drosophila leads to decreased rhodopsin in adult photoreceptors. Decreased density of P-face particles in photoreceptor membrane (rhabdomeric microvilli) is a prominent ultrastructural feature of this rhodopsin deficiency. When adults are fed carotenoid, the rhabdomeric P-face particle density-which reflects the concentration of rhodopsin-increases halfway to the replete control level during the first 12 hours, and is fully restored by 2 days. Based on freeze-fracture replicas, there is a continuity of membrane between rhabdomeric microvilli and the parent retinula cell. That confluence is relevant to turnover of photoreceptive membrane. Microvillar and retinula cell P-face particle densities covary. The relevance of the demonstration of rapid recovery from chromophore depletion is discussed in relation to hypotheses that the chromophore and/or related retinoids regulate opsin gene transcription, and/or post-translational processing and deployment from the endoplasmic reticulum to the rhabdomere.

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“…Previously, we had shown a decrease in visual sensitivity, visual pigment and P-face particle density in retinoid deprived Drosophila Stark, 1977 ;Stark, Ivanyshyn and Hu, 1976 ;Stark and Zitzmann, 1976) followed by fast recovery upon chromophore replacement (Chen and Stark, 1992 ;Sapp et al, 1991 ;Stark and White, 1996). Opsinpromoter-CAT-reporter analyses in Drosophila and Northern blot analyses in flies * For correspondence and reprint requests.…”

Section: Introductionmentioning

confidence: 99%