RESUMO
Stochastic gene expression leads to inherent variability in expression outcomes even in isogenic single-celled organisms grown in the same environment. The Drop-Seq technology facilitates transcriptomic studies of individual mammalian cells, and it has had transformative effects on the characterization of cell identity and function based on single-cell transcript counts. However, application of this technology to organisms with different cell size and morphology characteristics has been challenging. Here we present yeastDrop-Seq, a yeast-optimized platform for quantifying the number of distinct mRNA molecules in a cell-specific manner in individual yeast cells. Using yeastDrop-Seq, we measured the transcriptomic impact of the lifespan-extending compound mycophenolic acid and its epistatic agent guanine. Each treatment condition had a distinct transcriptomic footprint on isogenic yeast cells as indicated by distinct clustering with clear separations among the different groups. The yeastDrop-Seq platform facilitates transcriptomic profiling of yeast cells for basic science and biotechnology applications.
Assuntos
Perfilação da Expressão Gênica/métodos , Regulação Fúngica da Expressão Gênica/genética , RNA Mensageiro/genética , Saccharomyces cerevisiae/genética , Análise de Célula Única/métodos , Transcriptoma/genética , Análise por Conglomerados , Regulação Fúngica da Expressão Gênica/efeitos dos fármacos , Ontologia Genética , Guanina/metabolismo , Guanina/farmacologia , Ácido Micofenólico/metabolismo , Ácido Micofenólico/farmacologia , RNA Mensageiro/metabolismo , Saccharomyces cerevisiae/citologia , Análise de Sequência de RNA/métodos , Transcriptoma/efeitos dos fármacosRESUMO
Although double-strand break (DSB) repair is essential for a cell's survival, little is known about how DSB repair mechanisms are affected by age. Here we characterize the impact of cellular aging on the efficiency of single-strand annealing (SSA), a DSB repair mechanism. We measure SSA repair efficiency in young and old yeast cells and report a 23.4% decline in repair efficiency. This decline is not due to increased use of non-homologous end joining. Instead, we identify increased G1 phase duration in old cells as a factor responsible for the decreased SSA repair efficiency. Expression of 3xCLN2 leads to higher SSA repair efficiency in old cells compared with expression of 1xCLN2, confirming the involvement of cell-cycle regulation in age-associated repair inefficiency. Examining how SSA repair efficiency is affected by sequence heterology, we find that heteroduplex rejection remains high in old cells. Our work provides insights into the links between single-cell aging and DSB repair efficiency.
