Retinal accumulation of the phosducin/T beta gamma and transducin complexes in developing normal mice and in mice and dogs with inherited retinal degeneration.
Rod photoreceptors of mammalian retinas contain a 33-kDa phosphoprotein, phosducin, which complexes with the beta, gamma-subunits of transducin (T beta gamma). The level of phosducin phosphorylation is modulated by light, suggesting that the phosducin/T beta gamma complex has a pivotal role in light-regulated events that occur in photoreceptors. We have investigated, in developing mouse retinas, the age at which the complex is first detected and the subsequent accumulation of the phosducin/T beta gamma complex during postnatal life. Western blot analysis detected immunoreactivity both for phosducin and T beta in retinal homogenates of 3-day-old mice. Thereafter, the level of immunoreactivity for both proteins increased steadily, to reach adult levels in the next 2 postnatal weeks. Gel filtration analysis of extracts from immature mouse retina showed that phosducin and T beta co-eluted, like the phosducin/T beta gamma complex of adult retina, as a 77-kDa complex, indicating that the phosducin/T beta gamma complex is formed when photoreceptors first synthesize the components of the complex. While the levels of the phosducin/T beta gamma complex increased steadily during the first 2 postnatal weeks, the subunits of transducin complex, T alpha together with additional amounts of T beta gamma, only started to appear around the 7-9th postnatal day, and the level of transducin complex increased sharply at 11-14 days to reach adult levels that are similar to those of phosducin/T beta gamma complex.(ABSTRACT TRUNCATED AT 250 WORDS)
Department of Anatomy and Cell Biology, University of California, Los Angeles.
R H
RH
Lee
B S
BS
Lieberman
R N
RN
Lolley
D000818:Animals; D002851:Chromatography, High Pressure Liquid; D004285:Dogs; D005136:Eye Proteins / Q000378:metabolism*; D020555:GTP-Binding Protein Regulators; D046911:Macromolecular Substances; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008817:Mice, Mutant Strains; D010750:Phosphoproteins / Q000378:metabolism*; D012016:Reference Values; D012160:Retina / Q000254:growth & development* / Q000378:metabolism; D012162:Retinal Degeneration / Q000235:genetics / Q000378:metabolism*; D015293:Transducin / Q000378:metabolism*
D005136:Eye Proteins; D020555:GTP-Binding Protein Regulators; D046911:Macromolecular Substances; D010750:Phosphoproteins; C065631:phosducin; D015293:Transducin