Gene expression underlying the effects of biotin deficiency in rat liver, worms and yeast

Biotin is cofactor of crucial enzymes for intermediary metabolism, and its deficiency affects the transcription of some critical genes of mammalian glucose metabolism. However, the precise mechanisms of biotin starvation on gene expression are unknown. Here we show that metabolic changes ushered by deficiency of this vitamin sets in motion extensive reorganization of carbon metabolism gene expression, consistent across three diverse eukaryotes, that is mediated through a regulatory circuitry at the genome level similar in the three species. We used affymetrix microarrays to detail the global gene expression underlying the effects of biotin deficiency in Rattus norvegicus liver, Caenorhabditis elegans and Saccharomyces cerevisiae and identified distinct classes of up-regulated genes during this event. Five male rats (Wistar strain) aged 21 days and 50g of weight were made biotin-deficient, and another five rats of similar gender, age and weight served as controls. Nematodes synchronized in L1 stage grown in minimal medium (MM) with 5 and 0.05 nM of biotin (sufficient and deficient, respectively). Biotin-deficient cultures of yeast were obtained by growing cells overnight in a defined synthetic minimal (SD) media with dextrose as the principal carbon source (2%) and (NH4)2SO4 as nitrogen source with aminoacids, minerals and vitamins as complements but without biotin. Cells were centrifuged, washed, and used to inoculate cultures in MMY with 0.4nM and 8nM of biotin adjusted to an A600 absorbance of 0.04 by triplicate. Cells were harvested when cultures reached an A600 absorbance of 0.6-0.8.