Csm4-Dependent Telomere Movement on Nuclear Envelope Promotes Meiotic Recombination

During meiotic prophase, chromosomes display rapid movement, and their telomeres attach to the nuclear envelope and cluster to form a “chromosomal bouquet.” Little is known about the roles of the chromosome movement and telomere clustering in this phase. In budding yeast, telomere clustering is promoted by a meiosis-specific, telomere-binding protein, Ndj1. Here, we show that a meiosis-specific protein, Csm4, which forms a complex with Ndj1, facilitates bouquet formation. In the absence of Csm4, Ndj1-bound telomeres tether to nuclear envelopes but do not cluster, suggesting that telomere clustering in the meiotic prophase consists of at least two distinct steps: Ndj1-dependent tethering to the nuclear envelope and Csm4-dependent clustering/movement. Similar to Ndj1, Csm4 is required for several distinct steps during meiotic recombination. Our results suggest that Csm4 promotes efficient second-end capture of a double-strand break following a homology search, as well as resolution of the double-Holliday junction during crossover formation. We propose that chromosome movement and associated telomere dynamics at the nuclear envelope promotes the completion of key biochemical steps during meiotic recombination

Genetic Improvement for Meat Production and Quality using Physiological Traits and DNA Markers and Possibility of Disease Resistance in Pigs

This paper reports results from a seven-generation genetic selection experiment to develop an excellent line of Duroc breed in meat production and meat quality traits. It also describes genetic correlations between meat quality and various production traits and physiological traits such as serum insulin like growth factor 1 (IGF-1) and leptin concentration. This study introduces the possibility of genetic improvement using DNA marker for Duroc pigs. Recently, pork that is produced without antibiotic feed additives is demanded internationally, thereby necessitating some other means to improve pigs\u27 disease resistance. A pig-breeding program for the goal of higher disease resistance has begun. This report presents the possibility of genetic improvement of pig\u27s disease resistance based on statistical breeding theory, on DNA marker information, and on its actual implementation

Genetic Analysis of Baker's Yeast Msh4-Msh5 Reveals a Threshold Crossover Level for Meiotic Viability

During meiosis, the Msh4-Msh5 complex is thought to stabilize single-end invasion intermediates that form during early stages of recombination and subsequently bind to Holliday junctions to facilitate crossover formation. To analyze Msh4-Msh5 function, we mutagenized 57 residues in Saccharomyces cerevisiae Msh4 and Msh5 that are either conserved across all Msh4/5 family members or are specific to Msh4 and Msh5. The Msh5 subunit appeared more sensitive to mutagenesis. We identified msh4 and msh5 threshold (msh4/5-t) mutants that showed wild-type spore viability and crossover interference but displayed, compared to wild-type, up to a two-fold decrease in crossing over on large and medium sized chromosomes (XV, VII, VIII). Crossing over on a small chromosome, however, approached wild-type levels. The msh4/5-t mutants also displayed synaptonemal complex assembly defects. A triple mutant containing a msh4/5-t allele and mutations that decreased meiotic double-strand break levels (spo11-HA) and crossover interference (pch2Δ) showed synergistic defects in spore viability. Together these results indicate that the baker's yeast meiotic cell does not require the ∼90 crossovers maintained by crossover homeostasis to form viable spores. They also show that Pch2-mediated crossover interference is important to maintain meiotic viability when crossovers become limiting

Chromosome architecture and homologous recombination in meiosis

Meiocytes organize higher-order chromosome structures comprising arrays of chromatin loops organized at their bases by linear axes. As meiotic prophase progresses, the axes of homologous chromosomes align and synapse along their lengths to form ladder-like structures called synaptonemal complexes (SCs). The entire process of meiotic recombination, from initiation via programmed DNA double-strand breaks (DSBs) to completion of DSB repair with crossover or non-crossover outcomes, occurs in the context of chromosome axes and SCs. These meiosis-specific chromosome structures provide specialized environments for the regulation of DSB formation and crossing over. In this review, we summarize insights into the importance of chromosome architecture in the regulation of meiotic recombination, focusing on cohesin-mediated axis formation, DSB regulation via tethered loop-axis complexes, inter-homolog template bias facilitated by axial proteins, and crossover regulation in the context of the SCs. We also discuss emerging evidence that the SUMO and the ubiquitin-proteasome system function in the organization of chromosome structure and regulation of meiotic recombination

THEORETICAL STUDIES ON THE TRAVERSE AND NON-TRAVERSE MOTION IN WINDING

ArticleJournal of the Faculty of Textile Science and Technology, Shinshu University. Ser. B, Engineering 9: 1-15(1967)departmental bulletin pape

Weekly Teriparatide Therapy Rapidly Accelerates Bone Healing in Pyogenic Spondylitis with Severe Osteoporosis

Pyogenic spondylitis is a frequently observed disease in orthopedics, and the number of cases is increasing. Some patients with pyogenic spondylitis suffer from vertebral destruction due to infection. The disease is typically treated with antibiotics, bed rest, spinal support, and lesion curettage; however, vigorous drug therapy against vertebral body destruction by pyogenic spondylitis has not been attempted. In this report, a case of pyogenic spondylitis with spinal destruction caused by infection and treated with once-weekly teriparatide administration is presented. Vertebral body erosion in cortical and cancellous areas by the infection was rapidly repaired after 6 weeks of once-weekly teriparatide treatment. Treatment with once-weekly teriparatide appears to be a new strategy for patients with severe osteoporosis suffering from pyogenic spondylitis

Effect of nitrogen, phosphorus and calcium fertilizations on the yield and quality of Fj-hybrid tomato seed

The effect of nitrogen (N), phosphorus (P), and calcium (Ca) fertilizations on the seed yield and quality of F ^hybrid tomato seed grown by NFT were investigated. Higher N application (8 me/I) at the onset of flowering increased seed yield. Increasing N level at later growth stage increased seed yield of upper cluster, therefore total seed per plant also high. Four me/I ofCa level combined with 8 me/I ofP level increased in the weight of fruit and seed. However, at the case of 8 me/I ofCa, increasing P level declined fruit and seed yield severely. Especially when both P and Ca level were high (8 me/I), fruit and seed yield markedly decreased into about 60 %. Effect ofN content in the seed will reflect to the N compounds constituent there and consequently may influence seed germination. Keywords: F-hybrid tomato seed production - nutrient film technique (NFT) - nitrogen - phosphorus - calcium â