Streptococcus pyogenes is a ubiquitous and versatile pathogen that causes a variety of infections with a wide range of severity. The versatility of this organism is due in part to its capacity to regulate virulence gene expression in response to the many environments that it encounters during an infection. We analyzed the expression of two potential virulence factors, sagA and siaA (also referr...

In this study, Simulated Annealing (SA) and Genetic Algorithm (GA) soft computing techniques are integrated to estimate optimal process parameters that lead to a minimum value of machining performance. Two integration systems are proposed, labeled as integrated SAGA -type1 and integrated SAGA -type2. The approaches proposed in this study involve six modules, which are experimental data, regress...

The conserved multi-subunit Ccr4-Not complex regulates gene expression in diverse ways. In this work, we characterize the suppression of temperature sensitivity associated with a mutation in the gene encoding the scaffold subunit of the Ccr4-Not complex, NOT1, by the deletion of SPT3. We determine that the deletion of SPT3, but not the deletion of genes encoding other subunits of the SAGA compl...

Yeast TAF90p is a component of at least two transcription regulatory complexes, the general transcription factor TFIID and the Spt-Ada-Gcn5 histone acetyltransferase complex (SAGA). Broad transcription defects have been observed in mutants of other TAF(II)s shared by TFIID and SAGA but not in the only two TAF90 mutants isolated to date. Given that the numbers of mutants analyzed thus far are sm...

In Saccharomyces cerevisiae, many osmotically inducible genes are regulated by the Sko1p-Ssn6p-Tup1p complex. On osmotic shock, the MAP kinase Hog1p associates with this complex, phosphorylates Sko1p, and converts it into an activator that subsequently recruits Swi/Snf and SAGA complexes. We have found that phospholipase C (Plc1p encoded by PLC1) is required for derepression of Sko1p-Ssn6p-Tup1...

The Saccharomyces cerevisiae SAGA (Spt-Ada-Gcn5-acetyltransferase) complex functions as a coactivator during Gal4-activated transcription. A functional interaction between the SAGA component Spt3 and TATA-binding protein (TBP) is important for TBP binding at Gal4-activated promoters. To better understand the role of SAGA and other factors in Gal4-activated transcription, we selected for suppres...

The recent case of Terri Schiavo has been an important medical, legal, and ethical controversy. However, much of the public discussion of the tragedy has been based on inaccurate information regarding the facts of the case and the actual legal and ethical issues involved. This article reviews the pertinent aspects of the case and the ethical and legal questions raised and highlights the lessons...

The SAGA chromatin modifying complex functions as a transcriptional coactivator for a large number of genes, and SAGA dysfunction has been linked to carcinogenesis and neurodegenerative disease. The protein complex is comprised of approximately 20 subunits, arranged in a modular fashion, and includes 2 enzymatic subunits: the Gcn5 acetyltransferase and the Non-stop deubiquitinase. As we learn m...

Gene activation in eukaryotes requires chromatin remodeling complexes like Swi/Snf and histone acetylases like SAGA. How these factors are recruited to promoters is not yet understood. Using CHIP, we measured recruitment of Swi/Snf, SAGA, the repressor Ash1p, and transcription factors Swi5p and SBF to the HO endonuclease promoter as cells progress through the yeast cell cycle. Swi5p's entry int...

We previously showed that the Spt-Ada-Gcn5-acetyltransferase (SAGA) complex is recruited to the activated HXT2 and HXT4 genes and plays a role in the association of TBP-associated factors. Using the HXT2 and HXT4 genes, we now present evidence for a functional link between Snf1p-dependent activation, recruitment of the SAGA complex, histone H3 removal, and H3 acetylation. Recruitment of the SAG...