Transposition of the maize autonomous element Activator in transgenic Nicotiana plumbaginifolia plants

A pectin glucuronyltransferase gene is essential for intercellular attachment in the plant meristem

Intercellular attachment is an essential process in the morphogenesis of multicellular organisms. A unique mutant, nolac-H18 (nonorganogenic callus with loosely attached cells), generated by T-DNA transformation using leaf-disk cultures of haploid Nicotiana plumbaginifolia, lost the ability to form tight intercellular attachments and adventitious shoots. The gene tagged with T-DNA, named NpGUT1 (glucuronyltransferase 1), was similar to the gene for the catalytic domains of animal glucuronyltransferases and was expressed predominantly in shoot and root apical meristems. The transformation of NpGUT1 complemented the nolac-H18 mutation, and the expression of antisense NpGUT1 RNA produced crumbled shoots. The mutation caused defects in the glucuronic acid of rhamnogalacturonan II of pectin, which drastically reduced the formation of borate cross-linking of rhamnogalacturonan II. NpGUT1, which encodes a unique glucuronyltransferase, is a glycosyltransferase gene identified in pectin biosynthesis and is essential for intercellular attachment in plant meristems and tissues.

Cloning of AtMRP1, an Arabidopsis thaliana cDNA encoding a homologue of the mammalian multidrug resistance-associated protein

A cDNA encoding a putative ATP-binding cassette (ABC) transporter from Arabidopsis was cloned and sequenced based on an EST clone homologous to ABC sequences in other species. The cDNA is 5.5 kb long and contains an ORF encoding a 1623 amino acids protein. This sequence is the first MRP-like protein found in plants.

Analysis of splice donor and acceptor site function in a transposable gene trap derived from the maize element Activator

Gene trap vectors have been used in insertional mutagenesis in animal systems to clone genes with interesting patterns of expression. These vectors are designed to allow the expression of a reporter gene when the vector inserts into a transcribed region. In this paper we examine alternative splicing events that result in the expression of a GUS reporter gene carried on a Ds element which has been designed as a gene trap vector for plants. We have developed a rapid and reliable method based on PCR to study such events. Many splice donor sites were observed in the 3' Ac border. The relative frequency of utilisation of certain splice donor and acceptor sites differed between tobacco and Arabidopsis. A higher stringency of splicing was observed in Arabidopsis.