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. 2007 May 7;35(11):3612–3623. doi: 10.1093/nar/gkm273

Figure 3.

Figure 3.

Isolation of cDNA clones encoding proteins that bind to the A2 region of the GmCaM4 promoter. (A) Strategy for cDNA isolation by selection in yeast. Soybean cDNA libraries constructed in the yeast expression vector pAD-GAL4-2.1 were transformed into YM4271 cells carrying the dual reporter genes HIS3 and lacZ under the control of four tandem repeats of the A2 region of the GmCaM-4 promoter. The yeast expression cDNA libraries encode an N-terminal fusion of the GAL4 activation domain (AD) to soybean proteins. PminHIS3 indicates the minimal promoter of the HIS3 gene, and PminCYC1 indicates the CYC1 minimal promoter. PADH1 indicates the alcohol dehydrogenase 1 (ADH1) promoter, and TADH1 indicates the ADH1 terminator. (B) Specific interactions of GmZF-HD1 and −2 with the A2 region of the GmCaM-4 promoter. Yeast transformants harboring the indicated clones (upper left) were grown in the presence of 20 mM (upper right) or 60 mM (lower left) 3-AT. Nine of the 16 positive clones are shown in this figure. Numbers indicate representative clones as seen in Table 1. The β-galactosidase activity of yeast colonies grown in YPD medium was determined by a filter-lift assay (lower right).