Figure 4.—

Overexpression of YJL070c phenocopies the amd1 deletion mutant. (A) Effect of YJL070c or YBR284w overexpression on growth in the presence of adenine or hypoxanthine. Cells were transformed with the pCM189 empty plasmid (vector) or either the tet-YBR284w or tet-YJL070c plasmids. (B) Intracellular guanylic nucleotide content is specifically decreased in wild-type cells overexpressing YJL070c and grown in the presence of adenine. Wild-type (BY4742) cells were transformed with the pCM189 vector or plasmids allowing overexpression of AMD1, YJL070c, or YBR284w. Transformants were grown in SDcasaW medium supplemented or not with external adenine, and intracellular guanylic nucleotide content was measured as previously described (Breton et al. 2008). (C) Overexpression of YJL070c leads to derepression of the IMD2-LacZ fusion expression. Cells were cotransformed with IMD2-lacZ plasmid and either the vector or the plasmids allowing overexpression of AMD1 or YJL070c. Transformants were grown in SC medium supplemented or not with adenine (+A), guanine (+G), or hypoxanthine (+H). (D) Expression of IMD2-LacZ fusion is drastically increased in a amd1 mutant in the presence of adenine. Cells were transformed with a plasmid carrying a IMD2-lacZ fusion. Transformants were grown in SDcasaW medium supplemented or not with adenine (+A), guanine (+G), or hypoxanthine (+H).