Open AccessNicotinamide induces F ob1‐dependent plasmid integration into chromosome XII in S accharomyces cerevisiae
Author(s) -
Tripathi Kaushlendra,
Matmati Nabil,
Zzaman Shamsu,
Westwater Caroline,
Mohanty Bidyut K.
Publication year - 2012
Publication title -
fems yeast research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.991
H-Index - 92
eISSN - 1567-1364
pISSN - 1567-1356
DOI - 10.1111/j.1567-1364.2012.00844.x
Subject(s) - biology , plasmid , saccharomyces cerevisiae , homologous recombination , microbiology and biotechnology , autonomously replicating sequence , dna replication , gene , dna , genetics , origin of replication
In the ribosomal DNA ( rDNA ) array of S accharomyces cerevisiae, DNA replication is arrested by the F ob1 protein in a site‐specific manner that stimulates homologous recombination. The silent information regulator S ir2, which is loaded at the replication arrest sites by F ob1, suppresses this recombination event. A plasmid containing Fob1‐binding sites, when propagated in a yeast strain lacking SIR2 is integrated into the yeast chromosome in a FOB1 ‐dependent manner. We show that addition of nicotinamide ( NAM ) to the culture medium can stimulate such plasmid integration in the presence of SIR2 . Pulsed‐field gel electrophoresis analysis showed that plasmid integration occurred into chromosome XII . NAM ‐induced plasmid integration was dependent on FOB1 and on the homologous recombination gene RAD52 . As NAM inhibits several sirtuins, we examined plasmid integration in yeast strains containing deletions of various sirtuin genes and observed that plasmid integration occurred only in the absence of SIR2 , but not in the absence of other histone deacetylases. In the absence of PNC1 that metabolizes NAM , a reduced concentration of NAM was required to induce plasmid integration in comparison with that required in wild‐type cells. This study suggests that NAD metabolism and intracellular NAM concentrations are important in F ob1‐mediated r DNA recombination.