A Move1 AT-Rich DNA Binding Protein That Combines an HMG I-like DNA Binding Domain with a Putative Transcription Domain

There is growing evidence that AT-rich promoter elements play a role in transcription of plant genes. For the promoter of the nuclear gene for chloroplast glutamine synthetase from pea (GS2), the deletion of a 33-bp AT-rich sequence (box 1 native) from the 5'end of a GS2 promoter-P-glucuronidase (GUS) fusion resulted in a 10-fold reduction inGUS activity. The box 1 native element was used in gel shift analysis and two distinct complexes were detected. One complex is related to the low-mobility complex reported previously for AT-rich elements from severa1 other plant promoters. A multimer of the box 1 sequence was used to isolate a cDNA encoding an AT-rich DNA binding protein.(ATBP-I)..ATBP-? is nota highmobility group protein, but it is a nove1 protein that combines e-high-mobility group IIY-like DNA binding domain with a glutamine-rich putative transcriptional domain.