Submitted to: Plant Physiology
Publication Type: Abstract Only
Publication Acceptance Date: 6/1/1995
Publication Date: N/A
Technical Abstract: Asparagine synthetase (AS) catalyzes the glutamine-dependent amidation of aspartate, producing asparagine. A 8 kb genomic clone containing an entire alfalfa AS gene was isolated and sequenced. Like the human gene encoding this protein, the alfalfa AS gene is composed of 13 exons and 12 introns. The position of one intron is conserved in the human and alfalfa genes. AS appears to be encoded by a small family of genes in alfalfa. Gel blot hybridization to RNA isolated from various alfalfa tissues shows that the level of AS mRNA is high in nodules but undetectable in leaves, stems, roots and cotyledons. During nodule development, the level of AS mRNA increases some 15-fold in effective nodules but maintains low or undetectable level in nodules incapable of fixing nitrogen. To examine the regulation of AS gene, a 2.7 kb 5'-flanking region of the gene fused to the 3 glucuronidase (GUS) reporter gene was transformed into alfalfa. GUS activity throughout plant development will be reported.