Differential Scaling of Gene Expression with Cell Size May Explain Size Control in Budding Yeast.

Yeast cells must grow to a critical size before committing to division. It is unknown how size is measured. We find that as cells grow, mRNAs for some cell-cycle activators scale faster than size, increasing in concentration, while mRNAs for some inhibitors scale slower than size, decreasing in concentration.

The non-homologous end-joining pathway of S. cerevisiae works effectively in G1-phase cells, and religates cognate ends correctly and non-randomly.

DNA double-strand breaks (DSBs) are potentially lethal lesions repaired by two major pathways: homologous recombination (HR) and non-homologous end-joining (NHEJ). Homologous recombination preferentially reunites cognate broken ends. In contrast, non-homologous end-joining could ligate together any two ends, possibly generating dicentric or acentric fragments, leading to inviability.

Roles of the CDK phosphorylation sites of yeast Cdc6 in chromatin binding and rereplication.

The Saccharomyces cerevisiae Cdc6 protein is crucial for DNA replication. In the absence of cyclin-dependent kinase (CDK) activity, Cdc6 binds to replication origins, and loads Mcm proteins. In the presence of CDK activity, Cdc6 does not bind to origins, and this helps prevent rereplication.

Growth rate and cell size modulate the synthesis of, and requirement for, G1-phase cyclins at start.

In Saccharomyces cerevisiae, commitment to cell cycle progression occurs at Start. Progression past Start requires cell growth and protein synthesis, a minimum cell size, and G(1)-phase cyclins. We examined the relationships among these factors.

Metabolism of phenanthrene by brown bullhead liver microsomes.

We have investigated the regio- and stereoselective metabolism of phenanthrene by the liver microsomes of brown bullhead (Ameriurus nebulosus), a bottom dwelling fish species. The liver microsomes from untreated and 3-methylcholanthrene (3-MC)-treated brown bullheads metabolized phenanthrene at a rate of 14.1 and 20.

Metabolism of chrysene by brown bullhead liver microsomes.

We have investigated the regio- and stereoselective metabolism of chrysene, a four-ring symmetrical carcinogenic polycyclic aromatic hydrocarbon (PAH), by the liver microsomes of brown bullhead (Ameriurus nebulosus), a bottom-dwelling fish species. The liver microsomes from untreated and 3-methylcholanthrene (3-MC)-treated brown bullheads metabolized chrysene at the rate of 30.1 and 82.