Scintillation Counters for the D0 Muon Upgrade

We present the results of an upgrade to the D0 muon system. Scintillating counters have been added to the existing central D0 muon system to provide rejection for cosmic ray muons and out-of-time background, and to provide additional fast timing information for muons in an upgraded Tevatron. Performance and results from the 1994-1996 Tevatron run are presented.Comment: 30 pages, 25 postscript figure

A novel noncoding RNA processed by Drosha is restricted to nucleus in mouse

Noncoding RNAs constitute a huge repertoire of gene regulatory molecules. Our previous, fine-resolution characterization of a mouse meiotic recombination hotspot from chromosome 8 resulted in identification of 2.4-kb unspliced and polyadenylated noncoding mrhl RNA. The gene is expressed in multiple tissues and is also present in rat but absent in humans. Here we report that the mrhl RNA gets processed to a small 80-nucleotide (nt) RNA species and is mediated by the Drosha complex. We also observe that the 80-nt Drosha product could be processed further to a 22-nt small RNA by Dicer in an in vitro reaction. However, this 22-nt product was not detected in vivo. The 80-nt as well as the 2.4-kb full-length RNA are nuclear-localized, showing distinct punctate nuclear signal. The colocalization of the noncoding RNA with Drosha and Nucleolin suggests the nucleolus as the site of processing of the 2.4-kb primary transcript. Additional foci of the processed 80-nt RNA were also observed outside the nucleolus, suggesting its role in some specific chromatin domain(s). Thus, this study reports a novel noncoding mrhl RNA that is processed and restricted within the cell nucleus

Mapping of Post-translational Modifications of Transition Proteins, TP1 and TP2, and Identification of Protein Arginine Methyltransferase 4 and Lysine Methyltransferase 7 as Methyltransferase for TP2

In a unique global chromatin remodeling process during mammalian spermiogenesis, 90% of the nucleosomal histones are replaced by testis-specific transition proteins, TP1, TP2, and TP4. These proteins are further substituted by sperm-specific protamines, P1 and P2, to form a highly condensed sperm chromatin. In spermatozoa, a small proportion of chromatin, which ranges from 1 to 10% in mammals, retains the nucleosomal architecture and is implicated to play a role in transgenerational inheritance. However, there is still no mechanistic understanding of the interaction of chromatin machinery with histones and transition proteins, which facilitate this selective histone replacement from chromatin. Here, we report the identification of 16 and 19 novel post-translational modifications on rat endogenous transition proteins, TP1 and TP2, respectively, by mass spectrometry. By in vitro assays and mutational analysis, we demonstrate that protein arginine methyltransferase PRMT4 (CARM1) methylates TP2 at Arg71, Arg75, and Arg92residues, and lysine methyltransferase KMT7 (Set9) methylates TP2 at Lys88 and Lys91 residues. Further studies with modification-specific antibodies that recognize TP2K88me1 and TP2R92me1 modifications showed that they appear in elongating to condensing spermatids and predominantly associated with the chromatin-bound TP2. This work establishes the repertoire of post-translational modifications that occur on TP1 and TP2, which may play a significant role in various chromatin-templated events during spermiogenesis and in the establishment of the sperm epigenome