Faculty Opinions recommendation of Global analysis of mRNA decay and abundance in Escherichia coli at single-gene resolution using two-color fluorescent DNA microarrays.

ABSTRACT RNA degradation is an important factor in the regulation of gene expression. It allows organisms to quickly respond to changing environmental conditions by adapting the expression of individual genes. The stability of individual mRNAs within an organism varies considerably, contributing to differential amounts of proteins expressed. In this study we used DNA microarrays to analyze mRNA degradation in exponentially growing cultures of the extremely halophilic euryarchaeon Halobacterium salinarum NRC-1 on a global level. We determined mRNA half-lives for 1,717 open reading frames, 620 of which are part of known or predicted operons. Under the tested conditions transcript stabilities ranged from 5 min to more than 18 min, with 79% of the evaluated mRNAs showing half-lives between 8 and 12 min. The overall mean half-life was 10 min, which is considerably longer than the ones found in the other prokaryotes investigated thus far. As previously observed in Escherichia coli and Saccharomyces cerevisiae, we could not detect a significant correlation between transcript length and transcript stability, but there was a relationship between gene function and transcript stability. Genes that are known or predicted to be transcribed in operons exhibited similar mRNA half-lives. These results provide initial insights into mRNA turnover in a euryarchaeon. Moreover, our model organism, H. salinarum NRC-1, is one of just two archaea sequenced to date that are missing the core subunits of the archaeal exosome. This complex orthologous to the RNA degrading exosome of eukarya is found in all other archaeal genomes sequenced thus far.

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Faculty Opinions recommendation of Global analysis of mRNA decay intermediates in Saccharomyces cerevisiae.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.717951451.793456750 ◽

2012 ◽

Author(s):

Elmar Wahle

Keyword(s):

Saccharomyces Cerevisiae ◽

Mrna Decay ◽

Global Analysis

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Genome-Wide Screening Identifies Six Genes That Are Associated with Susceptibility to Escherichia coli Microcin PDI

Applied and Environmental Microbiology ◽

10.1128/aem.01704-15 ◽

2015 ◽

Vol 81 (20) ◽

pp. 6953-6963 ◽

Cited By ~ 5

Author(s):

Zhe Zhao ◽

Lauren J. Eberhart ◽

Lisa H. Orfe ◽

Shao-Yeh Lu ◽

Thomas E. Besser ◽

...

Keyword(s):

Escherichia Coli ◽

Atp Synthase ◽

Disulfide Bonds ◽

Gene Knockout ◽

Single Gene ◽

Site Directed Mutagenesis ◽

Content Type ◽

E Coli ◽

Synthase Inhibitor ◽

Loss Of Susceptibility

ABSTRACTThe microcin PDI inhibits a diverse group of pathogenicEscherichia colistrains. Coculture of a single-gene knockout library (BW25113;n= 3,985 mutants) against a microcin PDI-producing strain (E. coli25) identified six mutants that were not susceptible (ΔatpA, ΔatpF, ΔdsbA, ΔdsbB, ΔompF, and ΔompR). Complementation of these genes restored susceptibility in all cases, and the loss of susceptibility was confirmed through independent gene knockouts inE. coliO157:H7 Sakai. Heterologous expression ofE. coliompFconferred susceptibility toSalmonella entericaandYersinia enterocoliticastrains that are normally unaffected by microcin PDI. The expression of chimeric OmpF and site-directed mutagenesis revealed that the K47G48N49region within the first extracellular loop ofE. coliOmpF is a putative binding site for microcin PDI. OmpR is a transcriptional regulator forompF, and consequently loss of susceptibility by the ΔompRstrain most likely is related to this function. Deletion of AtpA and AtpF, as well as AtpE and AtpH (missed in the original library screen), resulted in the loss of susceptibility to microcin PDI and the loss of ATP synthase function. Coculture of a susceptible strain in the presence of an ATP synthase inhibitor resulted in a loss of susceptibility, confirming that a functional ATP synthase complex is required for microcin PDI activity. Intransexpression ofompFin the ΔdsbAand ΔdsbBstrains did not restore a susceptible phenotype, indicating that these proteins are probably involved with the formation of disulfide bonds for OmpF or microcin PDI.

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Minireview: The Neuroendocrine Regulation of Puberty: Is the Time Ripe for a Systems Biology Approach?

Endocrinology ◽

10.1210/en.2005-1136 ◽

2006 ◽

Vol 147 (3) ◽

pp. 1166-1174 ◽

Cited By ~ 192

Author(s):

Sergio R. Ojeda ◽

Alejandro Lomniczi ◽

Claudio Mastronardi ◽

Sabine Heger ◽

Christian Roth ◽

...

Keyword(s):

Global Analysis ◽

Single Gene ◽

Functional Integration ◽

Cell Communication ◽

Cell Interaction ◽

Specific Cell ◽

Gnrh Secretion ◽

Cell Functions ◽

Hierarchical Arrangement ◽

Cell Cell

The initiation of mammalian puberty requires an increase in pulsatile release of GnRH from the hypothalamus. This increase is brought about by coordinated changes in transsynaptic and glial-neuronal communication. As the neuronal and glial excitatory inputs to the GnRH neuronal network increase, the transsynaptic inhibitory tone decreases, leading to the pubertal activation of GnRH secretion. The excitatory neuronal systems most prevalently involved in this process use glutamate and the peptide kisspeptin for neurotransmission/neuromodulation, whereas the most important inhibitory inputs are provided by γ-aminobutyric acid (GABA)ergic and opiatergic neurons. Glial cells, on the other hand, facilitate GnRH secretion via growth factor-dependent cell-cell signaling. Coordination of this regulatory neuronal-glial network may require a hierarchical arrangement. One level of coordination appears to be provided by a host of unrelated genes encoding proteins required for cell-cell communication. A second, but overlapping, level might be provided by a second tier of genes engaged in specific cell functions required for productive cell-cell interaction. A third and higher level of control involves the transcriptional regulation of these subordinate genes by a handful of upper echelon genes that, operating within the different neuronal and glial subsets required for the initiation of the pubertal process, sustain the functional integration of the network. The existence of functionally connected genes controlling the pubertal process is consistent with the concept that puberty is under genetic control and that the genetic underpinnings of both normal and deranged puberty are polygenic rather than specified by a single gene. The availability of improved high-throughput techniques and computational methods for global analysis of mRNAs and proteins will allow us to not only initiate the systematic identification of the different components of this neuroendocrine network but also to define their functional interactions.

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Physiological Studies of Escherichia coli Strain MG1655: Growth Defects and Apparent Cross-Regulation of Gene Expression

Journal of Bacteriology ◽

10.1128/jb.185.18.5611-5626.2003 ◽

2003 ◽

Vol 185 (18) ◽

pp. 5611-5626 ◽

Cited By ~ 127

Author(s):

Eric Soupene ◽

Wally C. van Heeswijk ◽

Jacqueline Plumbridge ◽

Valley Stewart ◽

Daniel Bertenthal ◽

...

Keyword(s):

Gene Expression ◽

Escherichia Coli ◽

Dna Microarrays ◽

Degradation Products ◽

Regulatory Gene ◽

Regulation Of Gene Expression ◽

Nitrate Respiration ◽

Starch Degradation ◽

Strain Mg1655 ◽

Growth Defects

ABSTRACT Escherichia coli strain MG1655 was chosen for sequencing because the few mutations it carries (ilvG rfb-50 rph-1) were considered innocuous. However, it has a number of growth defects. Internal pyrimidine starvation due to polarity of the rph-1 allele on pyrE was problematic in continuous culture. Moreover, the isolate of MG1655 obtained from the E. coli Genetic Stock Center also carries a large deletion around the fnr (fumarate-nitrate respiration) regulatory gene. Although studies on DNA microarrays revealed apparent cross-regulation of gene expression between galactose and lactose metabolism in the Stock Center isolate of MG1655, this was due to the occurrence of mutations that increased lacY expression and suppressed slow growth on galactose. The explanation for apparent cross-regulation between galactose and N-acetylglucosamine metabolism was similar. By contrast, cross-regulation between lactose and maltose metabolism appeared to be due to generation of internal maltosaccharides in lactose-grown cells and may be physiologically significant. Lactose is of restricted distribution: it is normally found together with maltosaccharides, which are starch degradation products, in the mammalian intestine. Strains designated MG1655 and obtained from other sources differed from the Stock Center isolate and each other in several respects. We confirmed that use of other E. coli strains with MG1655-based DNA microarrays works well, and hence these arrays can be used to study any strain of interest. The responses to nitrogen limitation of two urinary tract isolates and an intestinal commensal strain isolated recently from humans were remarkably similar to those of MG1655.

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