Hypocotyl expression and light downregulation of the soybean tubulin gene, tubB1.

The tubB1 beta-tubulin gene of Glycine max (previously named s beta 1) is highly expressed only in rapidly elongating regions of etiolated seedling hypocotyls and this expression is strongly downregulated when the seedlings are exposed to light. Primer extension demonstrated that the gene was transcribed in these tissues and contained two sites of transcriptional initiation. To determine the mechanism regulating tubB1 expression, a chimeric reporter gene was constructed by fusing 5' upstream regions of tubB1 to a promoterless beta-glucuronidase (GUS) gene and these constructs were introduced into protoplasts by electroporation.

Limited expression of a diverged beta-tubulin gene during soybean (Glycine max [L.] Merr.) development.

We examined the developmental expression of a diverged soybean beta-tubulin gene (designated sb-1), which had been cloned and sequenced previously. A probe specific for the sb-1 gene was constructed from the 3' transcribed untranslated sequence. As a control, a more general probe for beta-tubulin genes and their transcripts was constructed from a highly conserved region of the third exon of another soybean beta-tubulin gene, sb-2.

The biochemistry of compounds with anti-microtubule activity in plant cells.

The experimental use of anti-microtubule compounds has revealed essential functions of microtubules in plant cytoskeletal arrays, including the pre-prophase band, the mitotic and meiotic spindles, the phragmoplast, and the cortical array. The most commonly used plant microtubule depolymerization compounds are colchicine, and several synthetic herbicides belonging to three different chemical classes, the dinitroanilines, phosphoric amides, and N-phenyl carbamates. Taxol, a secondary plant product, is the only drug found to promote the polymerization of plant microtubules.

Light Regulation of beta-Tubulin Gene Expression during Internode Development in Soybean (Glycine max [L.] Merr.).

The relationship between tubulin gene expression and cell elongation was explored in developing internodes of Glycine max (L.) Merr., using light as a variable to alter the rate of elongation.

Oryzalin, a dinitroaniline herbicide, binds to plant tubulin and inhibits microtubule polymerization in vitro.

The effects of oryzalin, a dinitroaniline herbicide, on chromosome behavior and on cellular microtubules (MTs) were examined by light microscopy and immunogold staining, respectively, in endosperm cells from Haemanthus katherinae Bak. Brief treatments with 1.0·10(-8) M oryzalin reduced markedly the migration rate of anaphase chromosomes and 1.