Generation and Characterization of an Allelic Series of Ets1 Gene Targeted Mice: Thymomegaly, Microsplenia and Defective Homeostatic Proliferation of Peripheral Lymphocytes of Ets1ΔVII but not Ets1S-\u3eA Mice

Ets1 is a member of the ETS transcription factor family with demonstrated roles in cell proliferation, migration, and survival. Alternative splicing of exon VII results in two distinct protein isoforms: full length Ets1 and Ets1ΔVII. These isoforms bear key distinctions regarding protein-protein interactions, DNA binding kinetics and transcriptional target specificity. Targeted disruption of both Ets1 isoforms (Ets1 null) in mice results in increased perinatal lethality, loss of detectable NK and NKT cell activity, and differentiation, proliferation and survival defects in B- and T-Iymphocytes. To further delineate the individual roles of Ets1 isoforms in vivo we have generated an allelic series of Ets1 gene targeted mice. One line expresses only the Ets1ΔVII isoform. These Ets1ΔVII mice present with increased perinatal lethality, thymomegaly, as well as variable splenic and peripheral lymphopenia. Rates of apoptosis were diminished in the thymus and increased in the spleen of homozygotes. Increased rates of cell proliferation were also observed in both spleen and thymus with concomitant reduction in expression of both Cdkn1b and Cdkn2a proteins. Statistically significant elevation in CD4-CD8+ and CD8+CD4+ thymocyte calculated cell mass was observed in homozygote thymuses. Diminished cellularity in the spleen was due to reductions in the numbers of lymphoid cells (CD19+, CD4+, and CD8+). Two putative Ets1 target genes important in thymopoiesis, CD44 and RUNX1 were found to be misexpressed in the thymuses of homozygous mutant mice. Collectively these results demonstrate that Ets1ΔVII results in apoptotic and differentiative defects in lymphocytes and these defects are associated with misregulation of the putative target genes CD44 and RUNX1. Another line of mice in this allelic series, Ets1S-\u3eA, contains serine to alanine conversions in a critical domain coded by exon VII. This mutation abrogates phosphorylation mediated inhibition of Ets1 DNA binding. These mice present with a minimal phenotype suggestive that this autoinhibitory process is not central to the phenotypes observed in Ets1ΔVII mice. Targeted ES cells have been generated for a third line of mice expressing only full-length Ets1. Our results have demonstrated that regulation of Ets1 isoforms represents a mechanism in the maintenance of normal lymphoid homeostasis

Measurement of the longitudinal and transverse cross-section in e^+e^- annihilation at sqrt(s)=35-44 GeV

An investigation of the polar angle distribution of charged hadrons is presented using data taken by the JADE experiment at the PETRA e^+e^- collider at centre-of-mass energies of 35 and 44 GeV. From fits to the polar angle distribution the longitudinal, sigma_L, and transverse, sigma_T, cross-section relative to the total hadronic are determined at an average energy scale of 36.6 GeV. The results are sigma_L/sigma_tot = 0.067 +/- 0.013, sigma_T/sigma_tot = 0.933 -/+ 0.013 where total errors are given and the results are exactly anti-correlated. Using the next-to-leading order QCD prediction for the longitudinal cross-section, the value alpha_S(36.6 GeV) = 0.150 +/- 0.025 of the strong coupling constant is obtained in agreement with the world average value of alpha_S evolved to an energy scale of 36.6 GeV.Comment: 12 pages, LaTeX2e, 5 .eps-files included, pennames.sty included, submitted to Phys. Lett.

Opportunities for farming in alpine countries – pathways to truly grassland-based beef and milk production in Austria and Switzerland

Farming in the alpine countries of Austria and Switzerland fulfils important economic, socio-cultural and ecological functions for society. However, even though both Austria and Switzerland have increasingly focused their agricultural policy towards ecology, in both countries negative environmental impacts of agriculture still have to be reduced massively

On QCD analysis of stucture function F2γF_2^{\gamma} in alternative approach

The alternative approach to QCD analysis of the photon structure function $F_2^{\gamma}$ is presented. It differs from the conventional one by the presence of the terms which in conventional approach appear in higher orders. We show that this difference concerns also the photonic parton distribution functions. In the alternative approach, the complete LO analysis of $F_2^{\gamma}$ can be performed as all required quantities are known. At the NLO, however, one of the coefficient function is so far not available and thus only the photonic parton distribution function can be computed and compared to those of standard approach. We discuss the numerical difference of these approaches at the LO and the NLO approximation and show that in case of $F_2^{\gamma}$ this difference is non-negligible and may play an important role in the analysis on photon data of the future experiments.Comment: 25 page

Poly(A)-tail profiling reveals an embryonic switch in translational control

Poly(A) tails enhance the stability and translation of most eukaryotic mRNAs, but difficulties in globally measuring poly(A)-tail lengths have impeded greater understanding of poly(A)-tail function. Here, we describe poly(A)-tail length profiling by sequencing (PAL-seq) and apply it to measure tail lengths of millions of individual RNAs isolated from yeasts, cell lines, Arabidopsis leaves, mouse liver, and zebrafish and frog embryos. Poly(A)-tail lengths were conserved between orthologous mRNAs, with mRNAs encoding ribosomal proteins and other “housekeeping” proteins tending to have shorter tails. As expected, tail lengths were coupled to translational efficiency in early zebrafish and frog embryos. However, this strong coupling diminished at gastrulation and was absent in non-embryonic samples, indicating a rapid developmental switch in the nature of translational control. This switch complements an earlier switch to zygotic transcriptional control and explains why the predominant effect of microRNA-mediated deadenylation concurrently shifts from translational repression to mRNA destabilization

SN1993J VLBI (I): The Center of the Explosion and a Limit on Anisotropic Expansion

Phase-referenced VLBI observations of supernova 1993J at 24 epochs, from 50 days after shock breakout to the present, allowed us to determine the coordinates of the explosion center relative to the quasi-stationary core of the host galaxy M81 with an accuracy of 45 micro-arcsec, and to determine the nominal proper motion of the geometric center of the radio shell with an accuracy of 9micro-arcsec/yr. The uncertainties correspond to 160 AU for the position and 160 km/s for the proper motion at the distance of the source of 3.63 Mpc. After correcting for the expected galactic proper motion of the supernova around the core of M81 using HI rotation curves, we obtain a peculiar proper motion of the radio shell center of only 320 +/- 160 km/s to the south, which limits any possible one-sided expansion of the shell. We also find that the shell is highly circular, the outer contours in fact being circular to within 3%. Combining our proper motion values with the degree of circular symmetry, we find that the expansion of the shockfront from the explosion center is isotropic to within 5.5% in the plane of the sky. This is a more fundamental result on isotropic expansion than can be derived from the circularity of the images alone. The brightness of the radio shell, however, varies along the ridge and systematically changes with time. The degree of isotropy in the expansion of the shockfront contrasts with the asymmetries and polarization found in optical spectral lines. Asymmetric density distributions in the ejecta or more likely in the circumstellar medium, are favored to reconcile the radio and optical results. We see no sign of any disk-like density distribution of the circumstellar material, with the average axis ratio of the radio shell of SN1993J being less than 1.04.Comment: 21 pages, LaTex + 5 Figures (encapulsated PostScript), Accepted for Publication in the Astrophysical Journa

Effect of recent R_p and R_n measurements on extended Gari-Krumpelmann model fits to nucleon electromagnetic form factors

The Gari-Krumpelmann (GK) models of nucleon electromagnetic form factors, in which the rho, omega, and phi vector meson pole contributions evolve at high momentum transfer to conform to the predictions of perturbative QCD (pQCD), was recently extended to include the width of the rho meson by substituting the result of dispersion relations for the pole and the addition of rho' (1450) isovector vector meson pole. This extended model was shown to produce a good overall fit to all the available nucleon electromagnetic form factor (emff) data. Since then new polarization data shows that the electric to magnetic ratios R_p and R_n obtained are not consistent with the older G_{Ep} and G_{En} data in their range of momentum transfer. The model is further extended to include the omega' (1419) isoscalar vector meson pole. It is found that while this GKex cannot simultaneously fit the new R_p and the old G_{En} data, it can fit the new R_p and R_n well simultaneously. An excellent fit to all the remaining data is obtained when the inconsistent G_{Ep} and G_{En} is omitted. The model predictions are shown up to momentum transfer squared, Q^2, of 8 GeV^2/c^2.Comment: 14 pages, 8 figures, using RevTeX4; email correspondence to [email protected] ; minor typos corrected, figures added, conclusions extende

New empirical fits to the proton electromagnetic form factors

Recent measurements of the ratio of the elastic electromagnetic form factors of the proton, G_Ep/G_Mp, using the polarization transfer technique at Jefferson Lab show that this ratio decreases dramatically with increasing Q^2, in contradiction to previous measurements using the Rosenbluth separation technique. Using this new high quality data as a constraint, we have reanalyzed most of the world e-p elastic cross section data. In this paper, we present a new empirical fit to the reanalyzed data for the proton elastic magnetic form factor in the region 0 < Q^2 < 30 GeV^2. As well, we present an empirical fit to the proton electromagnetic form factor ratio, G_Ep/G_Mp, which is valid in the region 0.1 < Q^2 < 6 GeV^2

Statistical fluctuations for the fission process on its decent from saddle to scission

We reconsider the importance of statistical fluctuations for fission dynamics beyond the saddle in the light of recent evaluations of transport coefficients for average motion. The size of these fluctuations are estimated by means of the Kramers-Ingold solution for the inverted oscillator, which allows for an inclusion of quantum effects.Comment: 12 pages, Latex, 5 Postscript figures; submitted to PRC e-mail: [email protected] www home page: http://www.physik.tu-muenchen.de/tumphy/e/T36/hofmann.htm