76 research outputs found
Meiosis-Specific Loading of the Centromere-Specific Histone CENH3 in Arabidopsis thaliana
Centromere behavior is specialized in meiosis I, so that sister chromatids of homologous chromosomes are pulled toward the same side of the spindle (through kinetochore mono-orientation) and chromosome number is reduced. Factors required for mono-orientation have been identified in yeast. However, comparatively little is known about how meiotic centromere behavior is specialized in animals and plants that typically have large tandem repeat centromeres. Kinetochores are nucleated by the centromere-specific histone CENH3. Unlike conventional histone H3s, CENH3 is rapidly evolving, particularly in its N-terminal tail domain. Here we describe chimeric variants of CENH3 with alterations in the N-terminal tail that are specifically defective in meiosis. Arabidopsis thaliana cenh3 mutants expressing a GFP-tagged chimeric protein containing the H3 N-terminal tail and the CENH3 C-terminus (termed GFP-tailswap) are sterile because of random meiotic chromosome segregation. These defects result from the specific depletion of GFP-tailswap protein from meiotic kinetochores, which contrasts with its normal localization in mitotic cells. Loss of the GFP-tailswap CENH3 variant in meiosis affects recruitment of the essential kinetochore protein MIS12. Our findings suggest that CENH3 loading dynamics might be regulated differently in mitosis and meiosis. As further support for our hypothesis, we show that GFP-tailswap protein is recruited back to centromeres in a subset of pollen grains in GFP-tailswap once they resume haploid mitosis. Meiotic recruitment of the GFP-tailswap CENH3 variant is not restored by removal of the meiosis-specific cohesin subunit REC8. Our results reveal the existence of a specialized loading pathway for CENH3 during meiosis that is likely to involve the hypervariable N-terminal tail. Meiosis-specific CENH3 dynamics may play a role in modulating meiotic centromere behavior
Genetic architecture of purple pigmentation and tagging of some loci to SSR markers in pearl millet, Pennisetum glaucum (L.) R. Br.
The effect of trisomy on meiotic behaviour of interchange complexes in pearl millet, Pennisetum americanum (L.) leeke
Association of abnormal cytogenetics at date of morphologic complete remission (CR) with overall (OS), disease-free survival (DFS) and higher relapse rate in acute myeloid leukemia (AML): Results from Cancer and Leukemia Group B (CALGB) 8461
Meiotic Abnormalities in Intergeneric Hybrids between Saccharum spontaneumand Erianthus arundinaceus (Gramineae)
The PPAR α/γ Agonist Saroglitazar Improves Insulin Resistance and Steatohepatitis in a Diet Induced Animal Model of Nonalcoholic Fatty Liver Disease
Abstract Insulin resistance and hepatic lipid accumulation constitute the metabolic underpinning of nonalcoholic steatohepatitis (NASH). We tested the hypothesis that saroglitazar, a PPAR α/γ agonist would improve NASH in the diet-induced animal model of NAFLD. Mice received chow diet and normal water (CDNW) or high fat western diet and ad lib sugar water (WDSW). After 12 weeks, WDSW fed mice were randomized to receive (1) WDSW alone, (2) WDSW + vehicle, (3) WDSW + pioglitazone or (4) WDSW + saroglitazar for an additional 12 weeks. Compared to mice on WDSW and vehicle controls, mice receiving WDSW + saroglitazar had lower weight, lower HOMA-IR, triglycerides, total cholesterol, and ALT. Saroglitazar improved steatosis, lobular inflammation, hepatocellular ballooning and fibrosis stage. NASH resolved in all mice receiving saroglitazar. These effects were at par with or superior to pioglitazone. Molecular analyses confirmed target engagement and reduced oxidative stress, unfolded protein response and fibrogenic signaling. Transcriptomic analysis further confirmed increased PPAR-target expression and an anti-inflammatory effect with saroglitazar. Lipidomic analyses demonstrated that saroglitazar also reduced triglycerides, diglycerides, sphingomyelins and ceramides. These preclinical data provide a strong rationale for developing saroglitazar for the treatment of NASH in humans
Non-reductional meiosis in aTriticum turgidum �Aegilops longissima hybrid and in backcrosses of its amphidiploid withT. turgidum (Poaceae)
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