Search results for "Biosynthesi"

A Candida albicans 37 kDa polypeptide with homology to the laminin receptor is a component of the translational machinery.

1998

A cDNA encoding a 37 kDa protein was isolated from an expression library using antibodies raised against mycelial cell walls fromCandida albicans.The 37 kDa protein has over 60% sequence identity with the 37 kDa laminin-binding protein (LBP) from humans and over 80% identity with the Yst proteins ofSaccharomyces cerevisiae. TheC. albicansprotein was named CaYst1. It was found in membrane and ribosome fractions but surprisingly, was not found in cell walls. Unlike the human LBP, CaYst1p does not bind laminin. These data indicate that CaYst1p is not a cell-surface receptor for laminin as has been proposed for the human LBP. Instead, like theS. cerevisiaeYst proteins, it appears to be a riboso…

Anthraquinones from Ophiorrhiza pumila tissue and cell cultures

1998

We have succeeded in initiating and establishing systems of tissue and cell cultures of Ophiorrhiza pumila. Examination of the constituents of the methanol extract of the cultured calli revealed the presence of 11 anthraquinones including two new ones whose structures have been rigorously proved using advanced spectroscopic methods. These findings demonstrated a remarkable difference in the constituents between the wild plants and the callus tissue or cultured cells; the former is devoid of anthraquinones and contains a variety of camptothecin-related alkaloids whereas the latter contains a significant amount of anthraquinones and shows no indication of the presence of alkaloids after sever…

Dual-targeting siRNAs.

2010

We have developed an algorithm for the prediction of dual-targeting short interfering RNAs (siRNAs) in which both strands are deliberately designed to separately target different mRNA transcripts with complete complementarity. An advantage of this approach versus the use of two separate duplexes is that only two strands, as opposed to four, are competing for entry into the RNA-induced silencing complex. We chose to design our dual-targeting siRNAs as Dicer substrate 25/27mer siRNAs, since design features resembling pre-microRNAs (miRNAs) can be introduced for Dicer processing. Seven different dual-targeting siRNAs targeting genes that are potential targets in cancer therapy have been develo…

THE SMALL PROTEIN SCO2038 CONTROLS TRYPTOPHAN BIOSYNTHESIS AND DIFFERENTIATION IN STREPTOMYCES COELICOLOR

The cellular regulatory factors comprise regulatory proteins, small RNA and small proteins. It is known that the product of small orfs (smorfs) can regulate the translation of downstream elements and also can encode functional peptides involved in the regulation of specific pathways (Ladoukakis E. et al.,2011). In particular, in the model streptomycete Sfreptomyces coelicolor, smorfs (about 100-300 nucleotides) were identified in some amino acid biosynthetic gene clusters such as in the tryptophan trpCXBA locus (Limauro D. et al., I 990; Hu DS. et al., 1999). In S. coelicolor the molecular mechanisms that regulate tryptophan (Trp) biosynthesis are poorly understood and, unlike the trp opero…

Addition of ammonia or amino acids to a nitrogen-depleted medium affects gene expression patterns in yeast cells during alcoholic fermentation

2007

Yeast cells require nitrogen and are capable of selectively using good nitrogen sources in preference to poor ones by means of the regulatory mechanism known as nitrogen catabolite repression (NCR). Herein, the effect of ammonia or amino acid addition to nitrogen-depleted medium on global yeast expression patterns in yeast cells was studied using alcoholic fermentation as a system. The results indicate that there is a differential reprogramming of the gene expression depending on the nitrogen source added. Ammonia addition resulted in a higher expression of genes involved in amino acids biosynthesis while amino acid addition prepares the cells for protein biosynthesis. Therefore, a high per…

Global translational repression induced by iron deficiency in yeast depends on the Gcn2/eIF2α pathway

2020

Iron is an essential element for all eukaryotic organisms because it participates as a redox active cofactor in a wide range of biological processes, including protein synthesis. Translation is probably the most energy consuming process in cells. Therefore, one of the initial responses of eukaryotic cells to stress or nutrient limitation is the arrest of mRNA translation. In first instance, the budding yeast Saccharomyces cerevisiae responds to iron deficiency by activating iron acquisition and remodeling cellular metabolism in order to prioritize essential over non-essential iron-dependent processes. We have determined that, despite a global decrease in transcription, mRNA translation is a…

The ATC1 gene encodes a cell wall-linked acid trehalase required for growth on trehalose in Candida albicans.

2004

After screening a Candida albicans genome data base, the product of an open reading frame (IPF 19760/CA2574) with 41% identity to Saccharomyces cerevisiae vacuolar acid trehalase (Ath1p) was identified and named Atc1p. The deduced amino acid sequence shows that Atc1p contains an N-terminal hydrophobic signal peptide and 20 potential sites for N-glycosylation. C. albicans homozygous mutants that lack acid trehalase activity were constructed by gene disruption at the two ATC chromosomal alleles. Analysis of these null mutants shows that Atc1p is localized in the cell wall and is required for growth on trehalose as a carbon source. An Atc1p endowed with acid trehalase activity was obtained by …

Ubiquitin ligase Rsp5p is involved in the gene expression changes during nutrient limitation inSaccharomyces cerevisiae

2009

Rsp5p is an essential ubiquitin ligase involved in many different cellular events, including amino acid transporters degradation, transcription initiation and mRNA export. It plays important role in both stress resistance and adaptation to the change of nutrients. We have found that ubiquitination machinery is necessary for the correct induction of the stress response SPI1 gene at the entry of the stationary phase. SPI1 is a gene whose expression is regulated by the nutritional status of the cell and whose deletion causes hypersensitivity to various stresses, such as heat shock, alkaline stress and oxidative stress. Its regulation is mastered by Rsp5p, as mutations in this gene lead to a lo…

The Lsm1-7/Pat1 complex binds to stress-activated mRNAs and modulates the response to hyperosmotic shock.

2018

RNA-binding proteins (RBPs) establish the cellular fate of a transcript, but an understanding of these processes has been limited by a lack of identified specific interactions between RNA and protein molecules. Using MS2 RNA tagging, we have purified proteins associated with individual mRNA species induced by osmotic stress, STL1 and GPD1. We found members of the Lsm1-7/Pat1 RBP complex to preferentially bind these mRNAs, relative to the non-stress induced mRNAs, HYP2 and ASH1. To assess the functional importance, we mutated components of the Lsm1-7/Pat1 RBP complex and analyzed the impact on expression of osmostress gene products. We observed a defect in global translation inhibition under…

Novel Glutamate–Putrescine Ligase Activity in Haloferax mediterranei: A New Function for glnA-2 Gene

2021

This article belongs to the Section Cellular Biochemistry.