Biochemical genetics of the circadian rhythm in Neurospora crassa: studies on the cel strain

Thesis/Dissertation · Tue Jan 01 04:00:00 EST 1985

OSTI ID:5179634

Lakin-Thomas, P L

In Neurospora crassa, the cel mutation lengthens the period of the circadian rhythm when the medium is supplemented with linoleic acid (18:2). Double mutant strains were constructed between cel and the clock mutants prd-1 and four alleles at the frq locus. It was found that: (1) the effect of 18:2 on cel was blocked by prd-1, i.e., prd-1 is epistatic to cel. (2) cel and frq interact such that the percent increase in the period produced by 18:2 was inversely proportional to the period of the frq parent. (3) Data from the literature on period effects in double mutant strains support a multiplicative rather than an additive model. A biochemical interpretation of these interactions is discussed, based on the control of flux through metabolic pathways. Because the cel strain is known to be deficient in the pantothenate derivative normally attached to the fatty acid synthetase (FAS) complex, the possibility that cel may affect other pantothenate-modified proteins was investigated. It was found that in the cel/sup +/ strain, five proteins of molecular weights (M/sub r/) 9000, 19,000, 22,000, 140,000, and 200,000 were labelled with (/sup 14/C)pantothenate. In the cel strain, only the 200 k (FAS) label was reduced in amount. Therefore, there is no evidence that cel affects circadian rhythmicity through any deficiency other than FAS. A biochemical model for circadian rhythmicity in Neurospora is presented. Oscillations in cytoplasmic and mitochondrial Ca/sup 2 +/ are proposed; clock mutations are postulated to affect Ca/sup 2 +/ transporters and the mitochondrial membrane; and phase-shifting effects are accounted for by changes in Ca/sup 2 +/ or ATP levels.

• Research Organization: California Univ., San Diego (USA)
• OSTI ID: 5179634
• Country of Publication: United States
• Language: English

Related Subjects

550401* -- Genetics-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALKALINE EARTH METAL COMPOUNDS
AMINO ACIDS
ATP
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL EFFECTS
BIOLOGY
CALCIUM COMPOUNDS
CARBON 14 COMPOUNDS
CARBOXYLIC ACIDS
CATIONS
CELL CONSTITUENTS
CELL MEMBRANES
CHARGED PARTICLES
CYTOPLASM
ENZYMES
FUNGI
GENETICS
HYDROXY ACIDS
IONS
ISOTOPE APPLICATIONS
KINETICS
LABELLED COMPOUNDS
LIGASES
LINOLEIC ACID
MATHEMATICAL MODELS
MEMBRANES
METABOLISM
MITOCHONDRIA
MONOCARBOXYLIC ACIDS
MUTANTS
MUTATIONS
NEUROSPORA
NUCLEOTIDES
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANOIDS
PANTOTHENIC ACID
PLANTS
PROTEINS
REACTION KINETICS
TRACER TECHNIQUES
VITAMIN B GROUP
VITAMINS