Genetic determination of the developmental program for maize scutellar alcohol dehydrogenase: Involvement of a recessive,trans-acting,temporal-regulatory gene

The developmental program of alcohol dehydrogenase (ADH) activity in the scutellum of maize strain R6-67 is different from that of W64A. The level of scutellar ADH activity in R6-67 remains relatively high during the course of early sporophytic development as compared to the commonly observed pattern. In the typical inbred strain W64A, the activity of ADH declines substantially during that period. The variance values from the crosses between R6-67 and W64A reveal that the trait is under genetic control. Detailed genetic analysis suggests that a single gene is responsible for the altered developmental program of ADH activity in R6-67. This gene meets the criteria for temporal regulatory genes and is different from Adh2, the structural gene which codes the ADH-2 isozyme. We have designated this gene as Adr1 (alcohol dehydrogenase regulator, #1). Adr1 is unlinked to Adh2. There is no de novo synthesis of ADH in the scutellum during germination, and the difference in the activity level reflects the difference in the amount of enzyme protein as demonstrated by density labeling and rocket immunoelectrophoresis. Thus, it appears that Adr1 may regulate the degradation of ADH.     

Developmental expression and biochemical characterization Nassarius obsoleta.

Electrophoretic analysis of catalase isozyme patterns of Nassarius obsoleta indicates that these isozymes are products of two separate loci. Five aminopeptidase isozymes have also been detected in N. obsoleta and the data suggest that at least two loci encode these aminopetidase isozymes. Experiments designed to test for the interconvertibility of the isozymes indicated that the two catalase isozymes and that two of the five aminopeptidase isozymes tested were not conformational artifacts but distinct genetic products. No change in catalase isozyme expression, but considerable quantitative variation in catalase specific activity was noted during early developmental stages of N. obsoleta. Both qualitative and quantitative changes were noted in aminopeptidase expression during early developmental stages. This paper also describes several physicochemical parameters for each of the two enzymes under study.     

Nomenclature for catalase genes

Summary Gene product: catalase (H₂O₂:H₂O₂ oxidoreductase, EC 1.11.1.6) Mnemonic:Cat0 Gene product number:2.1.11.1.6     

Genetic control of alcohol dehydrogenase isozymes in maize

By means of horizontal gel electrophoresis and the zymogram technique, genetic variants and the formation of a hybrid molecule of the enzyme alcohol dehydrogenase (ADH) have been found in Zea mays. Each inbred homozygous stock examined showed two types of ADH isozyme patterns: a fast faint zone and a slower deeply staining zone, both anode-migrating at pH 8.5. The variants found differed in that each of the ADH zones varied in its electrophoretic mobility when compared to its counterpart in the other strain. When appropriate genetic crosses were made, the resulting heterozygotes showed the parental ADH zones, and, in addition, a band of intermediate mobility was formed between the deep-staining ADH bands. However, in the fast-moving zone only the parental isozymes were represented in the heterozygote. The formation of the hybrid molecule and the apparent gene dosage effects support the hypothesis that ADH-2 in maize exists as a dimer, whereas ADH-1 may exist as a monomer.This work was supported by the U.S. Atomic Energy Commission, under contract No. AT(11-1)-1338.     

A procedure for the small-scale isolation of plant RNA suitable for RNA blot analysis

A small-scale method for the isolation of total RNA from plant tissue is described. The method provides RNA of suitable quantity and quality from 0.2 g fresh tissue for the detection of mRNA species by RNA blot analysis. The entire procedure is adapted to 1.5-ml microfuge tubes and takes less than 5 h. This method is well suited for the isolation of RNA from large numbers of samples or from samples of limited quantity.