该研究关注了拟南芥中GAPB基因的光依赖性表达，发现XXIII盒内有两个GATA元件。通过对25种GATA因子的分类，选取了I类和II类中的GATA-1和GATA-20进行过表达实验。结果显示，GATA-1能特异性结合XXIII盒中的GATA元件，并且也能与协同受光调控的GAPA基因启动子中的元件结合。因此，推测光可能通过调节GATA-1在GATA位点的结合来控制GAPA和GAPB基因的表达。
摘要：
We have previously identified a cis-acting element, named the XXIII box, that is essential for light-regulated expression of the nuclear gene GAPB, which encodes the B subunit of chloroplast glyceraldehyde-3-phosphate dehydrogenase from Arabidopsis thaliana. Examination of the sequences indicated that there are two GATA motifs within the XXIII box. Based on the degree of the amino-acid sequence identity in the DNA binding domains, we divided the 25 GATA factors encoded in the Arabidopsis genome into three classes. We chose GATA-1 and GATA-20 from Class I and Class II, which include the majority of GATA factors, for overexpression in an Escherichia coli expression system. Gel mobility shift assays showed that GATA-1, but not GATA-20, binds specifically to the two GATA motifs within the XXIII fragment. In addition, we showed that GATA-1 could also bind specifically to a cis-acting element in the promoter of the GAPA gene, which is coordinately regulated by light with the GAPB gene. Based on these results, we propose that light controls the expression of GAPA and GAPB genes in part by regulating the binding of the same transcription factor at their GATA motifs.
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