Constitutive and inducible Saccharomyces cerevisiae promoters: evidence for two distinct molecular mechanisms

1986 ◽  
Vol 6 (11) ◽  
pp. 3847-3853
Author(s):  
K Struhl

his3 and pet56 are adjacent Saccharomyces cerevisiae genes that are transcribed in opposite directions from initiation sites that are separated by 200 base pairs. Under normal growth conditions, in which his3 and pet56 are transcribed at similar basal levels, a poly(dA-dT) sequence located between the genes serves as the upstream promoter element for both. In contrast, his3 but not pet56 transcription is induced during conditions of amino acid starvation, even though the critical regulatory site is located upstream of both respective TATA regions. Moreover, only one of the two normal his3 initiation sites is subject to induction. From genetic and biochemical evidence, I suggest that the his3-pet56 intergenic region contains constitutive and inducible promoters with different properties. In particular, two classes of TATA elements, constitutive (Tc) and regulatory (Tr), can be distinguished by their ability to respond to upstream regulatory elements, by their effects on the selection of initiation sites, and by their physical structure in nuclear chromatin. Constitutive and inducible his3 transcription is mediated by distinct promoters representing each class, whereas pet56 transcription is mediated by a constitutive promoter. Molecular mechanisms for these different kinds of S. cerevisiae promoters are proposed.

1986 ◽  
Vol 6 (11) ◽  
pp. 3847-3853 ◽  
Author(s):  
K Struhl

his3 and pet56 are adjacent Saccharomyces cerevisiae genes that are transcribed in opposite directions from initiation sites that are separated by 200 base pairs. Under normal growth conditions, in which his3 and pet56 are transcribed at similar basal levels, a poly(dA-dT) sequence located between the genes serves as the upstream promoter element for both. In contrast, his3 but not pet56 transcription is induced during conditions of amino acid starvation, even though the critical regulatory site is located upstream of both respective TATA regions. Moreover, only one of the two normal his3 initiation sites is subject to induction. From genetic and biochemical evidence, I suggest that the his3-pet56 intergenic region contains constitutive and inducible promoters with different properties. In particular, two classes of TATA elements, constitutive (Tc) and regulatory (Tr), can be distinguished by their ability to respond to upstream regulatory elements, by their effects on the selection of initiation sites, and by their physical structure in nuclear chromatin. Constitutive and inducible his3 transcription is mediated by distinct promoters representing each class, whereas pet56 transcription is mediated by a constitutive promoter. Molecular mechanisms for these different kinds of S. cerevisiae promoters are proposed.


1988 ◽  
Vol 8 (9) ◽  
pp. 3827-3836
Author(s):  
N P Williams ◽  
P P Mueller ◽  
A G Hinnebusch

Translational control of GCN4 expression in the yeast Saccharomyces cerevisiae is mediated by multiple AUG codons present in the leader of GCN4 mRNA, each of which initiates a short open reading frame of only two or three codons. Upstream AUG codons 3 and 4 are required to repress GCN4 expression in normal growth conditions; AUG codons 1 and 2 are needed to overcome this repression in amino acid starvation conditions. We show that the regulatory function of AUG codons 1 and 2 can be qualitatively mimicked by the AUG codons of two heterologous upstream open reading frames (URFs) containing the initiation regions of the yeast genes PGK and TRP1. These AUG codons inhibit GCN4 expression when present singly in the mRNA leader; however, they stimulate GCN4 expression in derepressing conditions when inserted upstream from AUG codons 3 and 4. This finding supports the idea that AUG codons 1 and 2 function in the control mechanism as translation initiation sites and further suggests that suppression of the inhibitory effects of AUG codons 3 and 4 is a general consequence of the translation of URF 1 and 2 sequences upstream. Several observations suggest that AUG codons 3 and 4 are efficient initiation sites; however, these sequences do not act as positive regulatory elements when placed upstream from URF 1. This result suggests that efficient translation is only one of the important properties of the 5' proximal URFs in GCN4 mRNA. We propose that a second property is the ability to permit reinitiation following termination of translation and that URF 1 is optimized for this regulatory function.


2021 ◽  
Vol 22 (22) ◽  
pp. 12583
Author(s):  
Qingsong Gao ◽  
Lei Liu ◽  
Haiying Zhou ◽  
Xi Liu ◽  
Wei Li ◽  
...  

Micronutrient metals, such as Mn, Cu, Fe, and Zn, are essential heavy metals for plant growth and development, while Cd is a nonessential heavy metal that is highly toxic to both plants and humans. Our understanding of the molecular mechanisms underlying Cd and micronutrient metal accumulation in plants remains incomplete. Here, we show that OsFWL7, an FW2.2-like (FWL) family gene in Oryza sativa, is preferentially expressed in the root and encodes a protein localized to the cell membrane. The osfwl7 mutation reduces both the uptake and the root-to-shoot translocation of Cd in rice plants. Additionally, the accumulation of micronutrient metals, including Mn, Cu, and Fe, was lower in osfwl7 mutants than in the wildtype plants under normal growth conditions. Moreover, the osfwl7 mutation affects the expression of several heavy metal transporter genes. Protein interaction analyses reveal that rice FWL proteins interact with themselves and one another, and with several membrane microdomain marker proteins. Our results suggest that OsFWL7 is involved in Cd and micronutrient metal accumulation in rice. Additionally, rice FWL proteins may form oligomers and some of them may be located in membrane microdomains.


1985 ◽  
Vol 5 (12) ◽  
pp. 3545-3551 ◽  
Author(s):  
J B McNeil ◽  
M Smith

Expression of the Saccharomyces cerevisiae CYC1 gene produces mRNA with more than 20 different 5' ends. A derivative of the CYC1 gene (CYC1-157) was constructed with a deletion of a portion of the CYC1 5'-noncoding region, which includes the sites at which many of the CYC1 mRNAs 5' ends map. A 54-mer double-stranded oligonucleotide homologous with the deleted sequence of CYC1-157 and which included a low level of random base pair mismatches (an average of two mismatches per duplex) was used to construct mutants of the CYC1 gene and examine the role of the DNA sequence at and immediately adjacent to the mRNA 5' ends in specifying their locations. The effect of these mutations on the site selection of mRNA 5' ends was examined by primer extension. Results indicate that there is a strong preference for 5' ends which align with an A residue (T in the template DNA strand) preceded by a short tract of pyrimidine residues.


2010 ◽  
Vol 21 (10) ◽  
pp. 1772-1782 ◽  
Author(s):  
Xia Li ◽  
Yunrui Du ◽  
Steven Siegel ◽  
Susan Ferro-Novick ◽  
Peter Novick

Inheritance of the endoplasmic reticulum (ER) requires Ptc1p, a type 2C protein phosphatase of Saccharomyces cerevisiae . Genetic analysis indicates that Ptc1p is needed to inactivate the cell wall integrity (CWI) MAP kinase, Slt2p. Here we show that under normal growth conditions, Ptc1p inactivates Slt2p just as ER tubules begin to spread from the bud tip along the cortex. In ptc1Δ cells, the propagation of cortical ER from the bud tip to the periphery of the bud is delayed by hyperactivation of Slt2p. The pool of Slt2p that controls ER inheritance requires the CWI pathway scaffold, Spa2p, for its retention at the bud tip, and a mutation within Slt2p that prevents its association with the bud tip blocks its role in ER inheritance. These results imply that Slt2p inhibits a late step in ER inheritance by phosphorylating a target at the tip of daughter cells. The PI4P5-kinase, Mss4p, is an upstream activator of this pool of Slt2p. Ptc1p-dependant inactivation of Slt2p is also needed for mitochondrial inheritance; however, in this case, the relevant pool of Slt2p is not at the bud tip.


2020 ◽  
Author(s):  
Kai Liu ◽  
Mingjuan Li ◽  
Bin Zhang ◽  
Yanchun Cui ◽  
Xuming Yin ◽  
...  

Abstract BackgroundGrain yield is a polygenic trait influenced by environmental and genetic interactions at all growth stages of the cereal plant. However, the molecular mechanisms responsible for coordinating the trade-off or cross-talk between these traits remain elusive.ResultsWe characterized the hitherto unknown function of four STRESS_tolerance and GRAIN_LENGTH (OsSGL) Poaceae ortholog genes, all encoding DUF1645 domain-containing proteins, in simultaneous regulation of grain length, grain weight, and drought stress-tolerance in rice. In normal growth conditions, the four ortholog genes were mainly expressed in the developing roots and panicles of the corresponding species. Over-expressing or heterologous high-level expressing Poaceae OsSGL ortholog genes conferred remarkably increased grain length, weight, and seed setting percentage, as well as significantly improved drought-stress tolerance in transgenic rice. Microscopical analysis also showed that the transgene expression promoted cell division and development. RNA-seq and qRT-PCR analyses revealed 73.8% (18,711) overlapped DEGs in all transgenic plants. Moreover, GO and KEGG analyses of different comparisons revealed that the key DEGs participating in drought stress-response belonged to hormone (especially auxin and cytokinin) pathways, and signaling processes were apparently affected in the young panicles. ConclusionTogether, these results suggest the four OsSGL orthologs perform a conserved function in regulating stress-tolerance and cell growth by acting via a hormone biosynthesis and signaling pathway. It may also induce a strategy for tailor-made crop yield improvement.


2021 ◽  
Author(s):  
Carla Oliveira ◽  
Ana Rita Guimarães ◽  
Inês Correia ◽  
Inês Sousa ◽  
Ana Poim ◽  
...  

AbstractThe complex biology of the human pathogen Candida albicans is reflected in its remarkable ability to proliferate in numerous body sites, adapt to drastic changes in the environment, form various types of colonies and grow in yeast, pseudo-hyphal and hyphal forms. Much has been learnt in recent years about the relevance of this phenotypic plasticity, but the mechanisms that support it are still not fully understood. We have demonstrated that atypical translation of the CUG codon is a source of unexpected morphological diversity. The CUG codon is translated as both leucine (Leu) (~3%) and serine (Ser) (~97%) in normal growth conditions, but Ser/Leu levels change in response to stress. Remarkably, recombinant C. albicans strains incorporating between 20% and 99% of Leu at CUG sites display a diverse array of phenotypes and produce colonies of variable morphology containing a mixture of yeast, pseudohyphal and hyphal cells. In this work we investigate the role of the CUG codon in the yeast-hypha transition. Our data show that increasing incorporation levels of Leu at CUG sites trigger hyphal initiation under non-inducing conditions by reducing farnesol production, and increasing the degradation of the Nrg1 hyphal repressor. We propose that dual CUG Ser/Leu translation triggers filamentation via the Nrg1 pathway.ImportanceThe unique translation of the CUG codon as both Ser (~97%) and Leu (~3%) plays a key role in the production of high genomic and phenotypic diversity in C. albicans. The molecular mechanisms that support such diversity are poorly understood. Here, we show that increased Leu incorporation at CUG sites induce hyphae formation in media where C. albicans normally grows in the yeast form. The data show that increasing Leu at CUG sites triggers the degradation of the hyphal repressor Nrg1, allowing for full expression of hyphal genes. Since filamentation is important for invasion of host tissues, this work shows how the atypical translation of a single codon may play a critical role in the virulence of all fungi of the CTG clade.


2008 ◽  
Vol 7 (6) ◽  
pp. 1009-1018 ◽  
Author(s):  
Jiyoti Verma-Gaur ◽  
Sudha Narayana Rao ◽  
Toshiki Taya ◽  
Parag Sadhale

ABSTRACT The Rpb4/Rpb7 subcomplex of yeast RNA polymerase II (Pol II) has counterparts in all multisubunit RNA polymerases from archaebacteria to higher eukaryotes. The Rpb4/7 subcomplex in Saccharomyces cerevisiae is unique in that it easily dissociates from the core, unlike the case in other organisms. The relative levels of Rpb4 and Rpb7 in yeasts affect the differential gene expression and stress response. Rpb4 is nonessential in S. cerevisiae and affects expression of a small number of genes under normal growth conditions. Here, using a chromatin immunoprecipitation (“ChIP on-chip”) technique, we compared genomewide binding of Rpb4 to that of a core Pol II subunit, Rpb3. Our results showed that in spite of being nonessential for survival, Rpb4 was recruited on coding regions of most transcriptionally active genes, similar to the case with the core Pol II subunit, Rpb3, albeit to a lesser extent. The extent of Rpb4 recruitment increased with increasing gene length. We also observed Pol II lacking Rpb4 to be defective in transcribing long, GC-rich transcription units, suggesting a role for Rpb4 in transcription elongation. This role in transcription elongation was supported by the observed 6-azauracil (6AU) sensitivity of the rpb4Δ mutant. Unlike most phenotypes of rpb4Δ, the 6AU sensitivity of the rpb4Δ strain was not rescued by overexpression of RPB7. This report provides the first instance of a distinct role for Rpb4 in transcription, which is independent of its interacting partner, Rpb7.


1990 ◽  
Vol 10 (6) ◽  
pp. 3262-3267 ◽  
Author(s):  
W R Boorstein ◽  
E A Craig

The SSA3 gene of Saccharomyces cerevisiae, a member of the HSP70 multigene family, is expressed at low levels under optimal growth conditions and is dramatically induced in response to heat shock. Sequences coinciding with two overlapping heat shock elements, located 156 base pairs upstream of the transcribed region, were necessary and sufficient for regulation of heat induction. The SSA3 promoter was also activated in an ssa1ssa2 double-mutant strain. This increase in the expression of SSA3 was mediated via the same upstream activating sequences that activated transcription in response to heat shock.


1984 ◽  
Vol 4 (2) ◽  
pp. 290-295 ◽  
Author(s):  
L Naumovski ◽  
E C Friedberg

A plasmid (pNF2000) containing a 9.7-kilobase pair DNA insert that complements the UV sensitivity of rad2-1, rad2-2, and rad2-4 mutants of Saccharomyces cerevisiae has been isolated from a yeast genomic library. Genetic analysis of strains derived by transformation of rad2 mutants with an integrating plasmid containing a 9.3-kilobase pair fragment from pNF2000 shows that the fragment integrates exclusively at the chromosomal rad2 gene. We therefore conclude that this plasmid contains the RAD2 gene. The 9.3-kilobase pair fragment was partially digested with Sau3A and cloned into a multicopy yeast vector designed for easy retrieval of Sau3A inserts. The smallest subclone that retains the RAD2 gene is 4.5 kilobase pairs. This fragment was partially digested with Sau3A and cloned into an integrating plasmid. These plasmids were isolated and integrated into a heterozygous rad2/RAD2 strain. Plasmids containing internal fragments of the RAD2 gene were identified because they yielded UV-sensitive transformants due to disruption of the RAD2 gene. Sporulation of diploids transformed with integrating plasmids containing internal fragments of RAD2 gave rise to four viable haploids per tetrad, indicating that unlike the RAD3 gene of S. cerevisiae, the RAD2 gene is not essential for the viability of haploid cells under normal growth conditions. Measurements of the RNA transcript by RNA-DNA hybridization with the internal fragment as the probe indicate a size of approximately 3.2 kilobases.


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