High impact information on VHT1

• VHR1 was identified in a complementation screening of mutagenized yeast cells that had lost the capacity to express the gene of the green fluorescent protein (GFP) from the VHT1 promoter [1].
• Vhr1p, a New Transcription Factor from Budding Yeast, Regulates Biotin-dependent Expression of VHT1 and BIO5 [1].
• Deltavhr1 deletion mutants fail to induce VHT1 on low biotin concentrations [1].
• Deletion and linker scanning analyses of the VHT1 promoter revealed the palindromic 18-nucleotide sequence AATCA-N(8)-TGAYT as the vitamin H-responsive element [1].
• Mutants lacking the plasma membrane biotin transporter Vht1p display constitutively high expression levels of biotin-responsive genes [2].

Biological context of VHT1

• After transformation of this mutant with a yeast genomic library, the unassigned open reading frame YGR065C was identified to complement this mutation [3].
• This demonstrates that Vht1p does not act as a sensor for biotin and that intracellular biotin is crucial for gene expression [2].

Regulatory relationships of VHT1

• Expression of YGR065C under the control of the constitutive ADH1 promoter resulted in very high biotin transport rates across the plasma membrane that were no longer regulated by the biotin concentration in the growth medium [3].

References