Rapid transcriptional regulation by phytochrome of the genes for phytochrome and chlorophyll a/b-binding protein in Avena sativa.

Abstract

We have examined phytochrome-regulated transcription of phytochrome (phy) and chlorophyll a/b binding protein (cab) genes in dark-grown Avena seedlings by using run-on

Regulation of Phytochrome Message Abundance in Root Caps of Maize

“…This low amount of Pfr may be achieved with only very low fluences of either red or far red light. Furthermore, this regulation results in an observed decrease in the abundance of phytochrome message due, at least in part, to a reduction in transcriptional activity (13). The response has been observed in maize seedlings (2), although to a lesser extent than seen in other species, such as oat (3), rice (10), and pea (26), and to a greater extent than in zucchini (12).…”

The Regulation of Enzymes Involved in Chlorophyll Biosynthesis

“…It has been shown that phytochrome depresses transcription of its own gene, phyA (Lissemore and Quail, 1988;Bruce and Quail, 1990;Dehesh et al, 1990;Bruce et al, 1991), and also the transcription of porA, the gene encoding POR (Batschauer and Apel, 1984;Mosinger et al, 1985). As a result of illumination, the inherently unstable phyA and porA mRNAs rapidly decline Colbert et al, 1985;Colbert, 1988).…”

Oat phytochrome A mRNA degradation appears to occur via two distinct pathways.

“…PHYA mRNA is inherently unstable, with an apparent half-life of 4 hr (Seeley et al, 1992). In 4-day-old dark-grown oat seedlings, the rate of PHYA transcription is high, producing an abundant mRNA (Lissemore and Quail, 1988). Within minutes after a red light pulse, transcription of the PHYA gene stops and is followed by a rapid decrease in PHYA mRNA levels as a result of the short half-life of the PHYA mRNA.…”