Diurnal Expression of Transducin mRNA and Translocation of Transducin in Rods of Rat Retina

作者：Mark R. Brann, Leslie V. Cohen · 发表于：Science · 年份：1987 · DOI：10.1126/science.3101175 · 被引用次数：232 · 研究领域：Retinal Development and Disorders、Retinoids in leukemia and cellular processes、Protein Kinase Regulation and GTPase Signaling

The messenger RNA (mRNA) that encodes alpha subunit of the guanosine triphosphate-binding protein transducin (T alpha) and T alpha immunoreactivity were localized and measured in the rat retina during the light-dark cycle with in situ hybridization and immunohistochemistry. Both T alpha mRNA and T alpha immunoreactivity were observed only in photoreceptors. Within the photoreceptor T alpha mRNA was present primarily in the inner segments and to a lesser extent in the outer nuclear layer at all times during the day and night. However, the distribution of T alpha immunoreactivity varied profoundly with the light-dark cycle; during the day, T alpha immunoreactivity was highest in the inner segments, and at night the outer segments were more immunoreactive. The amounts of T alpha mRNA and T alpha immunoreactivity also depended on the light-dark cycle. Levels of T alpha mRNA were high immediately before and after lights on; levels were low for the rest of the light-dark cycle. During the day, T alpha immunoreactivity increased in the inner segments following the increase in T alpha mRNA. After the lights were turned off, T alpha immunoreactivity decreased in the inner segments and increased in the outer segments. Thus, it appears that T alpha is synthesized in the inner segments after a morning increase in T alpha mRNA. Newly synthesized T alpha remains in the inner segments until it is transported to the outer segments at night, where it may be involved in the increase in the sen...