Search results for "repression"
showing 10 items of 92 documents
Multiple copies of SUC4 regulatory regions may cause partial de-repression of invertase synthesis in Saccharomyces cerevisiae.
1992
Transformation to generate multiple copies of regulatory DNA sequences has been used to study the interactions between regulatory proteins and their target sequences, since a high copy number of these sequences may titrate trans-acting regulatory proteins. We have analyzed the synthesis of invertase in yeast strains carrying different SUC genes transformed with the multiple-copy plasmid pSH143, a derivative of pJDB207 containing the promoter and upstream regulatory sequences of SUC4. The results obtained seem to be strain dependent. Under repressing conditions a high copy number of SUC4 promoter regions may cause increased expression of the invertase genes resulting in the synthesis of exte…
Inhibitory activities of short linear motifs underlie Hox interactome specificity in vivo
2015
Hox proteins are well-established developmental regulators that coordinate cell fate and morphogenesis throughout embryogenesis. In contrast, our knowledge of their specific molecular modes of action is limited to the interaction with few cofactors. Here, we show that Hox proteins are able to interact with a wide range of transcription factors in the live Drosophila embryo. In this context, specificity relies on a versatile usage of conserved short linear motifs (SLiMs), which, surprisingly, often restrains the interaction potential of Hox proteins. This novel buffering activity of SLiMs was observed in different tissues and found in Hox proteins from cnidarian to mouse species. Although th…
Transcriptional changes through menstrual cycle reveal a global transcriptional derepression underlying the molecular mechanism involved in the windo…
2021
The human endometrium is a dynamic tissue that only is receptive to host the embryo during a brief time in the middle secretory phase, called the window of implantation (WOI). Despite its importance, regulation of the menstrual cycle remains incompletely understood. The aim of this study was to characterize the gene cooperation and regulation of menstrual cycle progression, to dissect the molecular complexity underlying acquisition of endometrial receptivity for a successful pregnancy, and to provide the scientific community with detailed gene co-expression information throughout the menstrual cycle on a user-friendly web-tool database. A retrospective gene co-expression analysis was perfor…
Il poliziotto di un regime totalitario. Vita e carriera di Giuseppe Gueli
2013
The aim of this essay is to retrace Giuseppe Gueli’s life and career: a police offi cer (member of the P.S., the Italian public safety), who had formed during the last years of the liberal period, and who went through Italian Fascism and its development into a totalitarian regime. Beginning his career alongside Cesare Mori, Gueli fi lled in fact relevant positions within the Italian police as it had been organized by Arturo Bocchini: at fi rst in Alto Adige (South Tyrol) to set up the awkward system of the border police, in the Thirties Gueli moved to Sicily where he led a second repression campaign against the mafi a and fi nally, during the Forties, he became chief of the Special Inspecto…
The expression level of GCNF affects fate choice during neural differentiation of PCC7 cells
2005
The nuclear receptor GCNF (NR6A1) is required for embryonic survival and development, and regulation of fertility. We used a transgenic approach to investigate its role in neural differentiation. As model we chose the embryonal carcinoma cell line PCC7, which reproducibly differentiates into a tissue-like pattern of neuronal and non-neuronal cells after exposure to retinoic acid (RA). The differentiation pattern of gcnf sense and antisense clones consistently indicated that the expression level of GCNF positively correlated with the development of the neuronal fate. Moreover, antisense clones failed to down-regulate expression of the key regulator of differentiation Oct4 during the initial …
Chromatin structure of the yeast SUC2 promoter in regulatory mutants
1992
We have previously suggested that two positioned nucleosomes are removed from the promoter of the Saccharomyces cerevisiae SUC2 gene upon derepression by glucose starvation. To gain further insight into the changes accompanying derepression at the chromatin level we have studied the chromatin structure of the SUC2 promoter in several mutants affecting SUC2 expression. The non-derepressible mutants snf1, snf2 and snf5 present a chromatin structure characteristic of the repressed state, irrespective of the presence or absence of glucose. The non-repressible mutants, mig1 and ssn6, as well as the double mutant snfs sn6 exhibit an opened chromatin structure even in the presence of glucose. Thes…
Functional citric acid cycle in an arcA mutant of Escherichia coli during growth with nitrate under anoxic conditions
1998
The operation of the citric acid cycle of Escherichia coli during nitrate respiration (anoxic conditions) was studied by measuring end products and enzyme activities. Excretion of products other than CO2, such as acetate or ethanol, was taken as an indication for a non-functional cycle. From glycerol, approximately 0.3 mol acetate was produced; the residual portion was completely oxidized, indicating the presence of a partially active citric acid cycle. In an arcA mutant devoid of the transcriptional regulator ArcA, glycerol was completely oxidized with nitrate as an electron acceptor, demonstrating derepression and function of the complete pathway. Glucose, on the other hand, was excreted …
Molecular events associated with glucose repression of invertase in Saccharomyces cerevisiae.
1986
When S. cerevisiae growing in the presence of glucose (repressive condition) was shifted to higher temperatures, invertase was secreted. This secretion required protein synthesis, but was independent of RNA formation (Mormeneo & Sentandreu 1982). In addition accumulation of invertasespecific messenger RNA occurred in the absence of protein synthesis but was expressed only after synthesis of protein. Invertase mRNA was continuously synthesized under repressive conditions and the levels of this mRNA were regulated by the presence of glucose. The hexose regulated the concentration of this mRNA at the level of transcription and/or by sensitization of this messenger RNA. The expression of the in…
DNase I sensitivity of the chromatin of the yeast SUC2 gene for invertase.
1986
The DNase I sensitivity of chromatin of the yeast SUC2 gene, which encodes two forms of invertase, has been studied both in the genome and in a multicopy plasmid carrying the gene and its flaking sequences. Whereas little if any difference in the DNase I sensitivity of the flanking regions was found between the repressed and the derepressed states, derepression of the gene was accompanied by a large increase in the sensitivity of the transcribed region. A well-defined DNase I hypersensitive site was found centered at approximately 120 bp downstream from the end of the coding region. This site seems to be flanked in the 3' non-coding region by strictly positioned nucleosomes, and the structu…