Ectopic Expression of the Maize Homeobox Genes ZmHox1a or ZmHox1b Causes Pleiotropic Alterations in the Vegetative and Floral Development of Transgenic Tobacco

Abstract

The ZmHox1a and ZmHox1b (for Zea mays homeobox) genes map on chromosomes 8 and 6, respectively. Both homeobox genes encode proteins that show 91% similarity and are transcribed simultaneously in meristematic and proliferating cells of the maize plant. To gain insight into the biological function of these genes, both open reading frames were expressed in tobacco, under the control of the cauliflower mosaic virus 35S promoter. The resulting transgenic ZmHox1a or ZmHox1b plants showed identical phenotypic alterations that fall into three classes: size reduction, formation of adventitious shoots, and homeotic floral transformations. Approximately 30% of the ZmHox1-expressing plants grew to only one-third of the wild-type size, and most axillary buds gave rise to lateral shoots. Flower abnormalities included formation of petaloid stamens and development of secondary flowers within the primary gynoecium. Therefore, the ectopic expression of the maize ZmHox1 homeobox gene products affects the vegetative as well as the reproductive phase of tobacco plants. All phenotypic alterations were transmitted to the next generation.

Saccharomyces cerevisiae FKBP12 binds Arabidopsis thaliana TOR and its expression in plants leads to rapamycin susceptibility

“…The PCR product was digested with Eco RV and Not I and cloned under control of the CAMV35S promoter in pRT103 digested with Xho I, klenow treated and subsequently digested with Not I. The expression cassette was then moved into the unique Asc I site of the pGPTVHygro binary vector [32]. This construction was introduced by electroporation in Agrobacterium tumefaciens cells and transformation of Arabidopsis plants was carried out by the floral dip method [33].…”

Functional Nonequivalency of Actin Isovariants inArabidopsis

“…However, it still seemed possible that ectopic expression of actins in transgenic plants would produce strong phenotypes and provide valuable information regarding the physiological roles of the actin subclasses. Ectopic expression has been widely used to analyze the role of a variety of novel gene products, including that of floral homeotic or organ identity genes in plants (Mizukami and Ma, 1992;Uberlacker et al, 1996;Jack et al, 1997;Kirk et al, 1998;Jang et al, 1999;Kater et al, 2000). However, this type of misexpression study has not been used to dissect the function of isovariants encoded by plant cytoskeletal gene family members, although this method has been successfully used to analyze the role of fly and animal cytoskeletal gene products (Hutchens et al, 1997;Kumar et al, 1997;Fyrberg et al, 1998).…”

Transcriptional activation by the PHD finger is inhibited through an adjacent leucine zipper that binds 14-3-3 proteins

“…A reporter was constructed by inserting two Gal4-UAS (upstream activation sequence) pentamers in front of the CaMV 35S-core promoter (UAS-core) controlling the β-glucuronidase (GUS) marker. As effectors, the Gal4DB, Gal4DB-PHD1a and Gal4DB-ZIP/PHDf1a coding regions were inserted into vector pRTΩNot (33) and expressed under the strong CaMV 35S promoter. Gal4DB-VP16 (27) served as a positive control, containing a fusion of the strong VP16 activation domain to the Gal4DB.…”