Disease relevance of HOL1

• HOL1 double mutants and, to a lesser extent, HOL1-1 single mutants show hypersensitivity to specific cations added to the growth medium, including Na+, Li+, Cs+, Be2+, guanidinium ion, and histidinol, but not K+, Rb+, Ca2+, or Mg2+ [1].

High impact information on HOL1

• HOL1 mutations confer novel ion transport in Saccharomyces cerevisiae [1].
• The uptake of cations, the dominance of the mutant alleles, and the relative inability of hol1 delta cells to take up histidinol or Na+ suggest that hol1 encodes an ion transporter [1].
• The HOL1-1-101 gene was cloned and used to generate a viable haploid strain containing a hol1 deletion mutation (hol1 delta) [1].
• Selection for spontaneous mutations that increase histidinol uptake by such HOL1 mutants resulted in mutations that abolish the putative start codon of a six-codon open reading frame located approximately 171 nucleotides downstream of the transcription initiation site and 213 nucleotides upstream of the coding region of HOL1 [2].
• The DNA sequence of HOL1 was determined, and it predicts a 65-kDa protein related to the major facilitator family (drug resistance subfamily) of putative transport proteins [2].

Biological context of HOL1

• Amino acid substitutions in membrane-spanning domains of Hol1, a member of the major facilitator superfamily of transporters, confer nonselective cation uptake in Saccharomyces cerevisiae [2].

Associations of HOL1 with chemical compounds

• Two classes of mutations were obtained: (i) those that altered the coding region of HOL1, conferring the ability to take up histidinol; and (ii) cis-acting mutations (selected in a mutant HOL1-1 background) that increased expression of the Hol1 protein [2].
• Selection for the ability of Saccharomyces cerevisiae cells to take up histidinol, the biosynthetic precursor to histidine, results in dominant mutations at HOL1 [2].

References