Mcm1p binding sites in the ARG1 promoter positively regulate ARG1 transcription and S. cerevisiae growth in the absence of arginine and Gcn4p

Inositol phosphate multikinase dependent transcriptional control

Production of lipid-derived inositol phosphates including IP4 and IP5 is an evolutionarily conserved process essential for cellular adaptive responses that is dependent on both phospholipase C and the inositol phosphate multikinase Ipk2 (also known as Arg82 and IPMK). Studies of Ipk2, along with Arg82 prior to demonstrating its IP kinase activity, have provided an important link between control of gene expression and IP metabolism as both kinase dependent and independent functions are required for proper transcriptional complex function that enables cellular adaptation in response to extracellular queues such as nutrient availability. Here we define a promoter sequence cis-element, 5'-CCCTAAAAGG-3', that mediates both kinase-dependent and independent functions of Ipk2. Using a synthetic biological strategy, we show that proper gene expression in cells lacking Ipk2 may be restored through add-back of two components: IP4/IP5 production and overproduction of the MADS box DNA binding protein, Mcm1. Our results are consistent with a mechanism by which Ipk2 harbors a dual functionality that stabilizes transcription factor levels and enzymatically produces a small molecule code, which together coordinate control of biological processes and gene expression.

Regulation of amino acid, nucleotide, and phosphate metabolism in Saccharomyces cerevisiae

Ever since the beginning of biochemical analysis, yeast has been a pioneering model for studying the regulation of eukaryotic metabolism. During the last three decades, the combination of powerful yeast genetics and genome-wide approaches has led to a more integrated view of metabolic regulation. Multiple layers of regulation, from suprapathway control to individual gene responses, have been discovered. Constitutive and dedicated systems that are critical in sensing of the intra- and extracellular environment have been identified, and there is a growing awareness of their involvement in the highly regulated intracellular compartmentalization of proteins and metabolites. This review focuses on recent developments in the field of amino acid, nucleotide, and phosphate metabolism and provides illustrative examples of how yeast cells combine a variety of mechanisms to achieve coordinated regulation of multiple metabolic pathways. Importantly, common schemes have emerged, which reveal mechanisms conserved among various pathways, such as those involved in metabolite sensing and transcriptional regulation by noncoding RNAs or by metabolic intermediates. Thanks to the remarkable sophistication offered by the yeast experimental system, a picture of the intimate connections between the metabolomic and the transcriptome is becoming clear.

SOCS5 and SOCS6 have similar expression patterns in normal and cancer tissues

In the present study, we investigated mRNA expression patterns of both SOCS5 and SOCS6 in various normal and cancer tissues using a commercially available Cancer Profiling Array. We found that SOCS5 and SOCS6 had similar expression patterns in most cancer and healthy individuals, suggesting that these two genes are transcriptionally co-regulated. Tissue-specific up- or down-regulation of SOCS5 and SOCS6 was observed in several cancer tissues. Most importantly, thyroid gland cancer tissues exhibited large reductions of both SOCS5 and SOCS6 expressions. In addition, mRNA and protein levels of SOCS6 were down-regulated in liver cancer tissues. The results from our study may contribute to understanding SOCS5 and SOCS6 expression regulation in various cancer tissues, and show that these two factors may be used for diagnosing cancer.