A review of recent E802 results

Some recent results are presented from AGS E802, a survey experiment which is studying reactions of 14.6 A {center dot} GeV beams of protons, {sup 16}O and {sup 28}Si on targets ranging from {sup 9}Be to {sup 197}Au. Spectra for the global forward and transverse energy are shown; in nucleus-nucleus collisions these two quantities are anticorrelated, consistent with a large amount of stopping. Slope parameters from inclusive particle spectra are presented, with the most interesting effect being an apparent heating'' of mid-rapidity protons which emerge from the collisions of the largest nuclei. Also given are preliminary data on the production of antiprotons. 8 refs., 4 figs., 1 tab

Spt2p Defines a New Transcription-Dependent Gross Chromosomal Rearrangement Pathway

Large numbers of gross chromosomal rearrangements (GCRs) are frequently observed in many cancers. High mobility group 1 (HMG1) protein is a non-histone DNA-binding protein and is highly expressed in different types of tumors. The high expression of HMG1 could alter DNA structure resulting in GCRs. Spt2p is a non-histone DNA binding protein in Saccharomyces cerevisiae and shares homology with mammalian HMG1 protein. We found that Spt2p overexpression enhances GCRs dependent on proteins for transcription elongation and polyadenylation. Excess Spt2p increases the number of cells in S phase and the amount of single-stranded DNA (ssDNA) that might be susceptible to cause DNA damage and GCR. Consistently, RNase H expression, which reduces levels of ssDNA, decreased GCRs in cells expressing high level of Spt2p. Lastly, high transcription in the chromosome V, the location at which GCR is monitored, also enhanced GCR formation. We propose a new pathway for GCR where DNA intermediates formed during transcription can lead to genomic instability

Skeletal muscle actin mRNA. Characterization of the 3' untranslated region.

Plasmids p749, p106, and p150 contain cDNA inserts complementary to rat skeletal muscle actin mRNA. Nucleotide sequence analysis indicates the following sequence relationships: p749 specifies codons 171 to 360; p150 specifies codons 357 to 374 together with 120 nucleotides of the 3'-non-translated region; p106 specifies the last actin amino acid codon, the termination codon and the entire 3' non-translated region. Plasmid p749 hybridized with RNA extracted from rat skeletal muscle, cardiac muscle, smooth (stomach) muscle, and from brain. It also hybridizes well with RNA extracted from skeletal muscle and brain of dog and chick. Plasmid p106 hybridized specifically with rat striated muscles (skeletal and cardiac muscle) mRNA but not with mRNA from rat stomach and from rat brain. It also hybridized to RNA extracted from skeletal muscle of rabbit and dog but not from chick. Thermal stability of the hybrids and sensitivity to S1 digestion also indicated substantial divergence between the 3' untranslated end of rat and dog skeletal muscle actins. The investigation shows that the coding regions of actin genes are highly conserved, whereas the 3' non-coding regions diverged considerably during evolution. Probes constructed from the 3' non-coding regions of actin mRNAs can be used to identify the various actin mRNA and actin genes