Keeping it safe: control of meiotic chromosome breakage.

Meiotic cells introduce numerous programmed DNA double-strand breaks (DSBs) into their genome to stimulate crossover recombination. DSB numbers must be high enough to ensure each homologous chromosome pair receives the obligate crossover required for accurate meiotic chromosome segregation. However, every DSB also increases the risk of aberrant or incomplete DNA repair, and thus genome instability.

Synthetic chromosome fusion: Effects on mitotic and meiotic genome structure and function.

We designed and synthesized , which is ∼21.6% shorter than native , the smallest chromosome in . was designed for attachment to another synthetic chromosome due to concerns surrounding potential instability and karyotype imbalance and is now attached to , yielding the first synthetic yeast fusion chromosome.

Optogenetic Control of Heterologous Metabolism in .

Multiobjective optimization of microbial chassis for the production of xenobiotic compounds requires the implementation of metabolic control strategies that permit dynamic distribution of cellular resources between biomass and product formation. We addressed this need in a previous study by engineering the T7 RNA polymerase to be thermally responsive. The modified polymerase is activated only after the temperature of the host cell falls below 18 °C, and cells that employ the protein to transcribe the heterologous lycopene biosynthetic pathway exhibit impressive improvements in productivity.