|Samac, Deborah - Debby|
Submitted to: Plant Physiology Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 8/2/1997
Publication Date: N/A
Technical Abstract: Asparagine synthetase (AS) catalyzes the glutamine-dependent amidation of aspartate, producing asparagine. An alfalfa AS cDNA and its corresponding genomic DNA clone (AS18) have been previously characterized. RNA and protein blot analyses show that the expression of this AS gene is enhanced in root nodules and dark adapted leaves. A construct containing the 2.7 kb 5'-flanking region of the AS genomic DNA starting 15 nt upstream of the translation start codon fused to the beta-glucuronidase (GUS) reporter gene was transformed into alfalfa. Analyses of the transgenic plants show that enhanced GUS activity was detected in root nodules and dark adapted leaves. This result indicates that the 2.7 kb 5' upstream region of AS18 contains elements that affect expression in root nodules and leaves. To further identify cis-acting element(s) of the AS promoter, constructs containing a series of nested deletion of AS promoter fused to GUS reporter gene have been prepared and transformed into alfalfa. GUS activity analysis of root nodules and dark adapted leaves for these transgenic plants will show which promoter elements control nodule and dark adapted leaf AS expression.