SummaryThe waxy (Wx) gene of rice encodes a granule-bound starch synthase (GBSS = waxy protein} required for the synthesis of amylose in endosperm.

The maize genome has been shown to contain six glutamine synthetase (GS) genes with at least four different expression patterns. Noncoding 3' gene-specific probes were constructed from all six GS cDNA clones and used to examine transcript levels in selected organs by RNA gel blot hybridization experiments. The transcript of the single putative chloroplastic GS2 gene was found to accumulate primarily in green tissues, whereas the transcripts of the five putative GS1 genes were shown to accumulate preferentially in roots. The specific patterns of transcript accumulation were quite distinct for the five GS1 genes, with the exception of two closely related genes.

Asada T, Sonobe S, Shibaoka H j1991) Microtubule translocation in the cytokinetic apparatus of cultured tobacco cells. Nature 350: 238-241

The small genome of Arabidopsis contains at least nine expressed P-tubulin (TUB) genes, in contrast to the large ge-nomes of vertebrate animals, which contain a maximum of seven expressed P-tubulin genes. In this study, we report the structures of seven new TUB genes (TUBP, TUB3, TUBB, TUB6, TUB7, TUB8, and TUB9) of Arabidopsis. The sequences of T U B l and TU64 had been reported previously. Sequence similarities and unique structural features suggest that the nine TUB genes evolved by way of three branches in the plant P-tubulin gene evolutionary tree. Two genes (TUBP and TUB3) encode the same 0-tubulin isoform; thus, the nine genes predict eight different P-tubulins. In contrast to the a-tubulin (TUA) genes with their divergent intron patterns, all nine TUB genes contain 2 introns at conserved positions. Noncoding 3'gene-specific hybridization probes have been constructed for all nine TUB genes and used in RNA gel blot analyses to demonstrate that all nine genes are transcribed. Two-dimensional protein immunoblot analyses have resolved at least seven different P-tubulin isoforms in Arabidopsis, indicating that most, if not all, of the TUB tranxripts are translated.

The small genome of Arabidopsis contains at least nine expressed P-tubulin (TUB) genes, in contrast to the large genomes of vertebrate animals, which contain a maximum of seven expressed P-tubulin genes. In this study, we report the structures of seven new TUB genes (TUBP, TUB3, TUBB, TUB6, TUB7, TUB8, and TUB9) of Arabidopsis. The sequences of T U B l and TU64 had been reported previously. Sequence similarities and unique structural features suggest that the nine TUB genes evolved by way of three branches in the plant P-tubulin gene evolutionary tree. Two genes (TUBP and TUB3) encode the same 0-tubulin isoform; thus, the nine genes predict eight different P-tubulins. In contrast to the a-tubulin (TUA) genes with their divergent intron patterns, all nine TUB genes contain 2 introns at conserved positions. Noncoding 3'gene-specific hybridization probes have been constructed for all nine TUB genes and used in RNA gel blot analyses to demonstrate that all nine genes are transcribed. Two-dimensional protein immunoblot analyses have resolved at least seven different P-tubulin isoforms in Arabidopsis, indicating that most, if not all, of the TUB tranxripts are translated.