Light represses transcription of asparagine synthetase genes in photosynthetic and nonphotosynthetic organs of plants

Journal Article · Tue Oct 01 00:00:00 EDT 1991 · Molecular and Cellular Biology; (United States)

DOI:https://doi.org/10.1128/MCB.11.10.4966· OSTI ID:5089965

Tsai, Fongying; Coruzzi, G ^[1]

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1. Rockefeller Univ., New York, NY (United States)

Asparagine synthetase (AS) mRNA in Pisum sativum accumulates preferentially in plants grown in the dark. Nuclear run-on experiments demonstrate that expression of both the AS1 and AS2 genes is negatively regulated by light at the level of transcription. A decrease in the transcriptional rate of the AS1 gene can be detected as early as 20 min after exposure to light. Time course experiments reveal that the levels of AS mRNA fluctuate dramatically during a normal light/dark cycle. This is due to a direct effect of light and not to changes associated with circadian rhythm. A novel finding is that the light-repressed expression of the AS1 gene is as dramatic nonphotosynthetic organs such as roots as it is in leaves. Experiments demonstrate that the small amount of light which passes through the soil is sufficient to repress AS1 expression in roots, indicating that light has a direct effect on AS1 gene expression in roots. The negative regulation of AS gene expression by light was shown to be a general phenomenon in plants which also occurs in nonlegumes such as Nicotiana plumbaginifolia and Nicotiana tabacum. Thus, the AS genes can serve as a model with which to dissect the molecular basis for light-regulated transcriptional repression in plants.

• DOE Contract Number: FG02-89ER14034
• OSTI ID: 5089965
• Journal Information: Molecular and Cellular Biology; (United States), Vol. 11:10; ISSN 0270-7306
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
LIGASES
GENE REGULATION
PHOTOSYNTHESIS
DAILY VARIATIONS
TRANSCRIPTION
INHIBITION
ASPARAGINE
LEAVES
MESSENGER-RNA
PISUM
ROOTS
SOILS
VISIBLE RADIATION
AMIDES
AMINO ACIDS
CARBOXYLIC ACIDS
CHEMICAL REACTIONS
ELECTROMAGNETIC RADIATION
ENZYMES
LEGUMINOSAE
MAGNOLIOPHYTA
MAGNOLIOPSIDA
NUCLEIC ACIDS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PLANTS
PROTEINS
RADIATIONS
RNA
SYNTHESIS
VARIATIONS
550200* - Biochemistry