Shusei Sato

Identification and characterization of genes induced during sexual differentiation in Schizosaccharomyces pombe

Five cDNA clones, harboring genetic messages preferentially expressed during the sexual differentiation process, were isolated from a cDNA library of Schizosaccharomyces pombe by subtractive screening. Transcription of the corresponding genes, termed isp3, 4, 5, 6, and 7, was dependent on nitrogen starvation and their induction occurred at several stages of spore formation. Analysis of the cDNA prmary structures revealed a capacity for the coding of polypeptides of 19.2 kDa, 88.3 kDa, 60.1 kDa, 49.7 kDa, and 43.8 kDa, respectively. The translated amino-acid sequences of isp5 and isp6 were found to show significant similarities to those of amino-acid permeases and proteinase B of Saccharomyces cerevisiae, respectively. Disruption of isp6 arrested the cell cycle prior to conjugation and caused a drastic blocking effect on spore formation.

Evidence of meiosis-specific regulation of gene expression in lily microsporocytes

Abstract Transfection experiments were performed with DNA constructs bearing the GUS reporter gene and various promoter elements to assess meiosis specificity of expression. Plasmid DNA, pBI221, including the CaM 35S promoter fused to the GUS gene, was expressed in protoplasts derived from lily calli and young anthers but not microsporocytes. In contrast, plasmid DNAs bearing the meiotic promoter mei2Pro (δ12) and mei2Pro (δ12-s) isolated from Schizosaccharomyces pombe, fused to the GUS gene, were expressed in protoplasts from lily microsporocytes but not from somatic cells. Furthermore, DNAs with a mutated mei2 promoter fused to the GUS gene showed reduced activity. Transfection of the plasmid DNA, pUC19-recA-mei2, bearing mei2Pro (δ12) in front of the E. coli recA gene, was associated with higher recombinogenic activities assayable in vitro. The induction of GUS in meiocytes by transfection of plasmid DNA was dependent on the presence of mei2, as shown by the reduction of activity when the promoter was mutated and the stage of meiosis. The developmentally regulated expression of a yeast promoter in plant cells demonstrated in this paper may be the first to be reported.

Genome Structure of Jatropha curcas L.

The recent progress in DNA sequencing technology has allowed us to acquire information on the structures of whole genomes of various agronomically important plants in a relatively short period of time. In order to understand the genetic systems carried by Jatropha curcas and to accelerate the process of molecular breeding, comprehensive analyses of genes and the genome of this plant have been conducted using both conventional and advanced technologies, and a large quantity of sequence data has been accumulated. The latest draft sequence of the genome of J. curcas is 297 Mb long, and is presumed to cover 99 % of the gene space, with an average GC content of 33.8 %. By combining with the transcriptome information, a total of 30,203 protein-encoding genes, in addition to the 17,575 transposon-related genes and 2,124 putative pseudogenes, were assigned to the genome. Information on the genomic sequences and genes is available at http://www.kazusa.or.jp/jatropha/.

Proanthocyanidin Biosynthesis in Forage Legumes with Especial Reference to the Regulatory Role of R2R3MYB Transcription Factors and Their Analysis in Lotus japonicus

Proanthocyanidins (condensed tannins) can play an important part in ruminant nutrition both by increasing ruminal efficiency and preventing pasture bloat. In this chapter we discuss the control of this pathway by transcription factors and focus particularly upon genes of the bHLH and R2R3MYB classes. Results from studies using transgenic approaches, tilling and similar techniques are discussed here.