Evolution of NCoR-1 and NCoR-2 corepressor alternative mRNA splicing in placental mammals.

ObjectiveThe NCoR-1 and NCoR-2 corepressors are products of an early gene duplication near the beginning of vertebrate evolution and play both overlapping and divergent roles in development and physiology. Alternative-splicing of NCoR-1 and NCoR-2 further customizes their functions. To better understand the evolutionary basis of this phenomenon we extended our prior study of NCoR-1 and NCoR-2 alternative-splicing to an expanded series of species.ResultsAlternative-splicing of NCoR-2 was observed in all vertebrates examined whereas alternative-splicing of NCoR-1 was largely limited to placental mammals. Notably the most prominent of the NCoR-1 alternative-splicing events specific to the placental lineage, in exon 37 that plays a key role in murine metabolism, mimics in many features an analogous alternative-splicing event that appeared in NCoR-2 much earlier at the beginning of the vertebrate radiation. Detection of additional alternative-splicing events, at exons 28 in NCoR-1 or NCoR-2, was limited to the Rodentia or Primates examined, indicating both corepressor paralogs continued to acquire additional splice variations more recently and independently of one another. Our results suggest that the NCoR-1/NCoR-2 paralogs have been subject to a mix of shared and distinct selective pressures, resulting in the pattern of divergent and convergent alternative-splicing observed in extant species

Corepressor diversification by alternative mRNA splicing is species specific.

BackgroundSMRT and NCoR are corepressor paralogs that help mediate transcriptional repression by a variety of transcription factors, including the nuclear hormone receptors. The functions of both corepressors are extensively diversified in mice by alternative mRNA splicing, generating a series of protein variants that differ in different tissues and that exert different, even diametrically opposite, biochemical and biological effects from one another.ResultsWe report here that the alternative splicing previously reported for SMRT appears to be a relatively recent evolutionary phenomenon, with only one of these previously identified sites utilized in a teleost fish and a limited additional number of the additional known sites utilized in a bird, reptile, and marsupial. In contrast, extensive SMRT alternative splicing at these sites was detected among the placental mammals. The alternative splicing of NCoR previously identified in mice (and shown to regulate lipid and carbohydrate metabolism) is likely to have arisen separately and after that of SMRT, and includes an example of convergent evolution.ConclusionsWe propose that the functions of both SMRT and NCoR have been diversified by alternative splicing during evolution to allow customization for different purposes in different tissues and different species

POST-TRANSCRIPTIONAL REGULATION OF MAMMALIAN HEAT SHOCK FACTORS

Heat shock transcription factors (HSFs) function to regulate the expression of heatshock proteins (hsps) or molecular chaperones in the cell. Mammalian cells have twowell-characterized HSFs, HSF1 and HSF2. HSF1 functions to regulate the stress-inducedexpression of hsps. The function of HSF2 appears to be in regulating hsp expressionduring development and differentiation.In this work, I describe two distinct HSF1 mRNA isoforms (HSF1-a and HSF1-b)that are generated by alternative splicing of the HSF1 pre-mRNA. The two HSF1 mRNAisoforms result from the inclusion (HSF1-a), or omission (HSF1-b), of a 66 nucleotideexon of the HSF1 gene, which encodes a 22 amino acid sequence. These results showthat the levels of the HSF1-a and HSF1-b mRNA isoforms are regulated in a tissuedependentmanner, with testis expressing predominantly the HSF1-b isoform while heartand brain express primarily the HSF1-a isoform.In addition, I describe two distinct HSF2 mRNA isoforms (HSF2-a and HSF2-b)that are generated by alternative splicing of the HSF2 pre-mRNA. The two HSF2 mRNAisoforms result from the inclusion (HSF2-a), or omission (HSF2-b), of a 54 nucleotideexon of the HSF2 gene, which encodes a 18 amino acid sequence. These results showthat the levels of the HSF2-a and HSF2-b mRNA isoforms are regulated in a tissuedependentmanner, with testis and brain expressing predominantly the HSF2-a isoformwhile heart, liver, and kidney express primarily the HSF2-b isoform. Furthermore, HSF2isoform levels are regulated both in a developmental and cell type dependent manner inthe testis. In a reporter assay, HSF2-a is a 2.6-fold better transcriptional activator thanthe HSF2-b isoform.We have demonstrated also that HSF2, but not HSF1 is a substrate for SUMO-1and SUMO-2 modification in vitro. Consistent with this, we have demonstrated thatHSF2 can interact with a portion of Ubc9, the SUMO-1 conjugating enzyme, in a twohybridassay. We have also shown that GFP-HSF2 colocalizes with SUMO-1 in discretenuclear domain structures in 7% of GFP-HSF2 expressing HeLa cells. Finally, we haveshown that lysine 82 of HSF2 is the primary site of SUMO-1 modification in vitro

2'-fucosyllactose Supplementation Improves Gut-Brain Signaling and Diet-Induced Obese Phenotype and Changes the Gut Microbiota in High Fat-Fed Mice.

Obesity is characterized by fat accumulation, chronic inflammation and impaired satiety signaling, which may be due in part to gut microbial dysbiosis. Manipulations of the gut microbiota and its metabolites are attractive targets for obesity treatment. The predominant oligosaccharide found in human milk, acts as a prebiotic with beneficial effects on the host. However, little is known about the beneficial effects of 2'-FL in obesity. The aim of this study was to determine the beneficial effects of 2'-FL supplementation on the microbiota-gut-brain axis and the diet-induced obese phenotype in high fat (HF)-fed mice. Male C57/BL6 mice (n = 6/group; six weeks old) were counter-balanced into six weight-matched groups and fed either a low-fat (LF; 10% kcal as fat), HF (45% kcal as fat) or HF diet with 2'-FL (HF_2'-FL) at 1, 2, 5 and 10% (w/v) in drinking water for six weeks. General phenotypes (body weight, energy intake, fat and lean mass), cecal microbiome and metabolites, gut-brain signaling, intestinal permeability and inflammatory and lipid profiles were assessed. Only 10% 2'-FL, but not 1, 2 or 5%, decreased HF diet-induced increases in energy intake, fat mass and body weight gain. A supplementation of 10% 2'-FL changed the composition of cecal microbiota and metabolites compared to LF- and HF-fed mice with an increase in Parabacteroides abundance and lactate and pyruvate, respectively, whose metabolic effects corresponded to our study findings. In particular, 10% 2'-FL significantly reversed the HF diet-induced impairment of cholecystokinin-induced inhibition of food intake. Gene expressions of interleukin (IL)-1β, IL-6, and macrophage chemoattractant protein-1 in the cecum were significantly downregulated by 10% 2'-FL compared to the HF group. Furthermore, 10% 2'-FL suppressed HF diet-induced upregulation of hepatic peroxisome proliferator-activated receptor gamma, a transcription factor for adipogenesis, at the gene level. In conclusion, 10% 2'-FL led to compositional changes in gut microbiota and metabolites associated with improvements in metabolic profiles and gut-brain signaling in HF-fed mice. These findings support the use of 2'-FL for modulating the hyperphagic response to HF diets and improving the microbiota-gut-brain axis

Changing Traditions: Supervision, Co-Teaching, and Lessons Learned in a Professional Development School Partnership

Considering how long societies have been educating their youth, the history of teacher education is relatively brief. The first efforts to provide systematic education for teachers with some kind of practical experience occurred in Rheims, France, in the late 17th century when Jean Baptiste De La Salle opened the first normal school

Symmetries and reversing symmetries of area-preserving polynomial mappings in generalised standard form

We determine the symmetries and reversing symmetries within G, the group of real planar polynomial automorphisms, of area-preserving nonlinear polynomial maps L in generalised standard form, L: x'=x+p(y), y'=y+q(x'), where p and q are polynomials. We do this by using the amalgamated free product structure of G. Our results lead to normal forms for polynomial maps in generalised standard form and to a classification of the group structures of the reversing symmetry groups for such maps.Comment: 22 page

Towards bounded wait-free PASIS

The PASIS read/write protocol implements a Byzantine fault-tolerant erasure-coded atomic register. The prototype PASIS storage system implementation provides excellent best-case performance. Writes require two round trips and contention- and failure-free reads require one. Unfortunately, even though writes and reads are wait-free in PASIS, Byzantine components can induce correct clients to perform an unbounded amount of work. In this extended abstract, we enumerate the avenues by which Byzantine servers and clients can induce correct clients to perform an unbounded amount of work in PASIS. We sketch extensions to the PASIS protocol and Lazy Verification that bound the amount of work Byzantine components can induce correct clients to perform. We believe that the extensions provide bounded wait-free reads and writes. We also believe that an implementation that incorporates these extensions will preserve the excellent best-case performance of the original PASIS prototype

Using Raman Spectroscopy to Improve Hyperpolarized Noble Gas Production for Clinical Lung Imaging Techniques

Spin-exchange optical pumping (SEOP) can be used to “hyperpolarize” 129Xe for human lung MRI. SEOP involves transfer of angular momentum from light to an alkali metal (Rb) vapor, and then onto 129Xe nuclear spins during collisions; collisions between excited Rb and N2 ensure that incident optical energy is nonradiatively converted into heat. However, because variables that govern SEOP are temperature-dependent, the excess heat can complicate efforts to maximize spin polarization—particularly at high laser fluxes and xenon densities. Ultra-low frequency Raman spectroscopy may be used to perform in situ gas temperature measurements to investigate the interplay of energy thermalization and SEOP dynamics. Experimental configurations include an “orthogonal” pump-and-probe design and a newer “inline” design (with source and detector on the same axis) that has provided a >20-fold improvement in SNR. The relationship between 129Xe polarization and the spatiotemporal distribution of N2 rotational temperatures has been investigated as a function of incident laser flux, exterior cell temperature, and gas composition. Significantly elevated gas temperatures have been observed—hundreds of degrees hotter than exterior cell surfaces—and variances with position and time can indicate underlying energy transport, convection, and Rb mass-transport processes that, if not controlled, can negatively impact 129Xe hyperpolarization