Furthermore, it was shown that the bZIP1 and bZIP53 are master transcription factors regulating the expression of ASN1, ProDH, and BCAT2, which are involved in amino acid catabolism and nitrogen translocation .
ASN1 and ASP3 are key enzymes of the biosynthesis of asparagine, which is utilized for intracellular nitrogen storage and nitrogen transport via vascular tissue especially when carbohydrate supply is limited .
It was reported that AtbZIP1 and AtbZIP53 bind to specific sequence motif elements, ACGT-box and ACTCAT-box, in the promoter regions of ProDH, ASN1, and BCAT .
Restriction fragment analysis of the secondary PCR product was done by digesting 15 [micro] L of product in a 40-mL total reaction volume consisting of 15 U of Ssp1 and 3 [micro] L of restriction buffer (Boehringer Mannheim Biochemicals, Indianapolis, IN) for species identification and Asn1 (Boehringer Mannheim) for genotyping in the same concentration at 37 [degrees] for 1 hour.
Restriction endonuclease digestion with Ssp1 of the secondary PCR 18S rRNA product yielded two fragments of 385 bp and 448 bp in size, while Asn1 digestion yielded two visible bands that were 102 bp and 731 bp.