Molecular quantification of Saccharomyces cerevisiae α-pheromone secretion

Rogers, David W.; McConnell, Ellen; Greig, Duncan

doi:10.1111/j.1567-1364.2012.00817.x

Cited by 16 publications

(32 citation statements)

References 24 publications

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“…We obtained secretion rates from significant fits (F-test p<0.05) of 9 images (see Text S1). The mean fitted value of the α -factor secretion rate of 865 molecules per second and MAT α cell is in good agreement with recent experimental measurements (550 molecules per second and cell measured as basal secretion with 2.5 - 4-fold maximal induction) [21], [22]. The fully parameterized model could now be used to efficiently calculate the entire α -factor distribution on arbitrary images.…”

Section: Resultssupporting

confidence: 85%

Yeast Mating and Image-Based Quantification of Spatial Pattern Formation

et al. 2014

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Communication between cells is a ubiquitous feature of cell populations and is frequently realized by secretion and detection of signaling molecules. Direct visualization of the resulting complex gradients between secreting and receiving cells is often impossible due to the small size of diffusing molecules and because such visualization requires experimental perturbations such as attachment of fluorescent markers, which can change diffusion properties. We designed a method to estimate such extracellular concentration profiles in vivo by using spatiotemporal mathematical models derived from microscopic analysis. This method is applied to populations of thousands of haploid yeast cells during mating in order to quantify the extracellular distributions of the pheromone α-factor and the activity of the aspartyl protease Bar1. We demonstrate that Bar1 limits the range of the extracellular pheromone signal and is critical in establishing α-factor concentration gradients, which is crucial for effective mating. Moreover, haploid populations of wild type yeast cells, but not BAR1 deletion strains, create a pheromone pattern in which cells differentially grow and mate, with low pheromone regions where cells continue to bud and regions with higher pheromone levels and gradients where cells conjugate to form diploids. However, this effect seems to be exclusive to high-density cultures. Our results show a new role of Bar1 protease regulating the pheromone distribution within larger populations and not only locally inside an ascus or among few cells. As a consequence, wild type populations have not only higher mating efficiency, but also higher growth rates than mixed MAT a bar1Δ/MAT α cultures. We provide an explanation of how a rapidly diffusing molecule can be exploited by cells to provide spatial information that divides the population into different transcriptional programs and phenotypes.

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Section: Resultssupporting

confidence: 85%

Yeast Mating and Image-Based Quantification of Spatial Pattern Formation

et al. 2014

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“…We expressed each predicted heterospecific mature pheromone as a single heterologous-pheromone-encoding unit within the dominant S. cerevisiae proprotein (MFa1 [20] or MFA1 [21]) under the endogenous promoter and terminator ( Figure S1). Each heterologous-pheromone-producing strain was tested for its ability to mate with S. cerevisiae cells of the opposite mating type (Figures 1 and S2).…”

Section: Resultsmentioning

confidence: 99%

Experimental Evolution of Species Recognition

et al. 2015

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Sex with another species can be disastrous, especially for organisms that mate only once, like yeast. Courtship signals, including pheromones, often differ between species and can provide a basis for distinguishing between reproductively compatible and incompatible partners. Remarkably, we show that the baker's yeast Saccharomyces cerevisiae does not reject mates engineered to produce pheromones from highly diverged species, including species that have been reproductively isolated for up to 100 million years. To determine whether effective discrimination against mates producing pheromones from other species is possible, we experimentally evolved pheromone receptors under conditions that imposed high fitness costs on mating with cells producing diverged pheromones. Evolved receptors allowed both efficient mating with cells producing the S. cerevisiae pheromone and near-perfect discrimination against cells producing diverged pheromones. Sequencing evolved receptors revealed that each contained multiple mutations that altered the amino acid sequence. By isolating individual mutations, we identified specific amino acid changes that dramatically improved discrimination. However, the improved discrimination conferred by these individual mutations came at the cost of reduced mating efficiency with cells producing the S. cerevisiae pheromone, resulting in low fitness. This tradeoff could be overcome by simultaneous introduction of separate mutations that improved mating efficiency alongside those that improved discrimination. Thus, if mutations occur sequentially, the shape of the fitness landscape may prevent evolution of the optimal phenotype--offering a possible explanation for the poor discrimination of receptors found in nature.

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“…Haploid cells are one of two mating types (a or α), and respond to the mating pheromone produced by haploid cells of the opposite mating type . The mating‐type‐specific agglutinins are only induced during mating between the two types of the haploid cells . In other words, the single‐type haploid cells would not express agglutinins because of no mating pheromones presence.…”

Section: Resultsmentioning

confidence: 99%

Display of heterologous proteins on the Saccharomyces cerevisiae surface display system using a single constitutive expression vector

Sun

Wang

Zhang

et al. 2013

Biotechnology Progress

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In this study, we constructed a novel and simple yeast surface display system with a single expression vector. The newly established system uses a bidirectional expression vector carrying the AGA1 gene driven by the PGK1 promoter in one direction and the AGA2-expression cassette driven by the TEF1 promoter in the reverse direction, and uses the geneticin, a G418-resistant gene, as the selection marker for transformants. Because all the display elements are put into one expression vector, the new system is much simpler to use, and there is no need for any genetic modification of the host strains; therefore, the new system can be used in wild type as well as laboratory strains of Saccharomyces cerevisiae. The display efficiency of heterologous proteins using the new system has been confirmed by displaying enhanced green fluorescent protein and Eimeria tenella (a chicken protozoan parasite) microneme protein2 (EtMic2) on several S. cerevisiae strains. We also tested the new system with an aga2 mutant strain of S. cerevisiae. The results indicate that the native expressed Aga2 protein has no effect on the display efficiency of heterologous proteins.

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Molecular quantification of Saccharomyces cerevisiae α-pheromone secretion

Cited by 16 publications

References 24 publications

Yeast Mating and Image-Based Quantification of Spatial Pattern Formation

Yeast Mating and Image-Based Quantification of Spatial Pattern Formation

Experimental Evolution of Species Recognition

Display of heterologous proteins on the Saccharomyces cerevisiae surface display system using a single constitutive expression vector

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