Upstream activating sequence

About: Upstream activating sequence is a research topic. Over the lifetime, 1633 publications have been published within this topic receiving 100112 citations.

Regulation of phospholipid synthesis in yeast by zinc.

Abstract: The yeast Saccharomyces cerevisiae has the ability to cope with a variety of stress conditions (e.g. zinc deficiency) by regulating the expression of enzyme activities including those involved with phospholipid synthesis. Zinc is an essential mineral required for the growth and metabolism of S. cerevisiae . Depletion of zinc from the growth medium of wild-type cells results in alterations in phospholipid composition including an increase in PI (phosphatidylinositol) and a decrease in phosphatidylethanolamine. These changes can be attributed to an increase in PIS1 -encoded PI synthase activity and a decrease in the activities of several CDP-diacylglycerol pathway enzymes including the CHO1 -encoded PS (phosphatidylserine) synthase. The reduction in PS synthase in response to zinc depletion is due to a repression mechanism that involves the UAS INO (inositol upstream activating sequence) element in the CHO1 promoter and the negative transcription factor Opi1p. These factors are also responsible for the inositol-mediated repression of CHO1 . This regulation may play an important role in allowing cells to adapt to zinc deficiency given the essential roles that phospholipids play in the structure and function of cellular membranes.

Transcriptional Regulation of the Human CD3γ Gene: The TATA-Less CD3γ Promoter Functions via an Initiator and Contiguous Sp-Binding Elements

Abstract: Growing evidence that the CD3gamma gene is specifically targeted in some T cell diseases focused our attention on the need to identify and characterize the elusive elements involved in CD3gamma transcriptional control. In this study, we show that while the human CD3gamma and CD3delta genes are oriented head-to-head and separated by only 1.6 kb, the CD3gamma gene is transcribed from an independent but weak, lymphoid-specific TATA-less proximal promoter. Using RNA ligase-mediated rapid amplification of cDNA ends, we demonstrate that a cluster of transcription initiation sites is present in the vicinity of the primary core promoter, and the major start site is situated in a classical initiator sequence. A GT box immediately upstream of the initiator binds Sp family proteins and the general transcription machinery, with the activity of these adjacent elements enhanced by the presence of a second GC box 10 nt further upstream. The primary core promoter is limited to a sequence that extends upstream to -15 and contains the initiator and GT box. An identical GT box located approximately 50 nt from the initiator functions as a weak secondary core promoter and likely generates transcripts originating upstream from the +1. Finally, we show that two previously identified NFAT motifs in the proximal promoter positively (NFATgamma(1)) or negatively (NFATgamma(1) and NFATgamma(2)) regulate expression of the human CD3gamma gene by their differential binding of NFATc1 plus NF-kappaB p50 or NFATc2 containing complexes, respectively. These data elucidate some of the mechanisms controlling expression of the CD3gamma gene as a step toward furthering our understanding of how its transcription is targeted in human disease.

Positive and negative transcriptional regulation by the yeast GAL11 protein depends on the structure of the promoter and a combination of cis elements

Abstract: GAL11 was first identified as a gene required for full expression of some galactose-inducible genes that are activated by GAL4, and it was subsequently shown to be necessary for full expression of another set of genes activated by RAP1/GRFl/TUF. Genetic analysis suggests that GAL11 functions as a coactivator, mediating the interaction of sequence-specific activators with basal transcription factors. To test this hypothesis, we first tried to identify functional domains by deletion analysis and found that the 866–910 region is indispensable for function. Using reporters bearing various upstream activating sequences (UAS) and different core promoter structures, we show that the involvement of GAL11 in transcriptional activation varies with the target promoter and the particular combination of cis elements. Gel electrophoresis in the presence of chloroquine shows that GAL11 affects the chromatin structure of a circular plasmid. Based on these findings, the role of GAL 11 in regulation of transcription, including an alteration in chromatin structure, is discussed.