The general transcription factor RAP30 binds to RNA polymerase II and prevents it from binding nonspecifically to DNA.

RAP30/74 is a human general transcription factor that binds to RNA polymerase II and is required for initiation of transcription in vitro regardless of whether the promoter has a recognizable TATA box (Z. F. Burton, M. Killeen, M. Sopta, L. G. Ortolan, and J. F. Greenblatt, Mol. Cell. Biol. 8:1602-1613, 1988). Part of the amino acid sequence of RAP30, the small subunit of RAP30/74, has limited homology with part of Escherichia coli sigma 70 (M. Sopta, Z. F. Burton, and J. Greenblatt, Nature (London) 341:410-414, 1989). To determine which sigmalike activities of RAP30/74 could be attributed to RAP30, we purified human RAP30 and a RAP30-glutathione-S-transferase fusion protein that had been produced in E. coli. Bacterially produced RAP30 bound to RNA polymerase II in the absence of RAP74. Both partially purified natural RAP30/74 and recombinant RAP30 prevented RNA polymerase II from binding nonspecifically to DNA. In addition, nonspecific transcription by RNA polymerase II was greatly inhibited by RAP30-glutathione-S-transferase. DNA-bound RNA polymerase II could be removed from DNA by partially purified RAP30/74 but not by bacterially expressed RAP30. Thus, the ability of RAP30/74 to recruit RNA polymerase II to a promoter-bound preinitiation complex may be an indirect consequence of its ability to suppress nonspecific binding of RNA polymerase II to DNA.

Characterization of a six-subunit holo-elongator complex required for the regulated expression of a group of genes in Saccharomyces cerevisiae.

The Elongator complex associated with elongating RNA polymerase II in Saccharomyces cerevisiae was originally reported to have three subunits, Elp1, Elp2, and Elp3. Using the tandem affinity purification (TAP) procedure, we have purified a six-subunit yeast Holo-Elongator complex containing three additional polypeptides, which we have named Elp4, Elp5, and Elp6. TAP tapping and subsequent purification of any one of the six subunits result in the isolation of all six components. Purification of Elongator in higher salt concentrations served to demonstrate that the complex could be separated into two subcomplexes: one consisted of Elp1, -2, and -3, and the other consisted of Elp4, -5, and -6. Deletions of the individual genes encoding the new Elongator subunits showed that only the ELP5 gene is essential for growth. Disruption of the two nonessential new Elongator-encoding genes, ELP4 and ELP6, caused the same phenotypes observed with knockouts of the original Elongator-encoding genes. Results of microarray analyses demonstrated that the gene expression profiles of strains containing deletions of genes encoding subunits of either Elongator subcomplex, in which we detected significantly altered mRNA expression levels for 96 genes, are very similar, implying that all the Elongator subunits likely function together to regulate a group of S. cerevisiae genes in vivo.

Incidence of hospitalized injuries among pregnant women in Maryland, 1979-1990.

INTRODUCTION: Injuries are a leading cause of morbidity among pregnant women. We compared injuries among pregnant women and all women of reproductive age in a large defined population. METHODS: Maryland hospital discharge data files from 1979-1990 were used to identify injuries in pregnant women and in all women 15-44 years of age. Injured pregnant women were defined as those hospitalized with concurrent ICD-9-CM discharge codes for injury and pregnancy. RESULTS: The 80,311 hospitalizations with injury of women 15-44 years old included 2,185 hospitalizations of pregnant women. The incidence of hospitalized injury per 100,000 person-years was 460 for pregnant women and 608 for all women 15-44 years old. Median length of stay and cost per hospitalization were 3.0 days and $1,478 for pregnant women and 4.0 days and $1,666 for all women 15-44 years old. Leading causes of hospitalized injury in pregnant women were poisonings (16.9%), fractures (14.7%), sprains (10.9%), and contusions (8.0%). Compared to all women 15-44 years of age, pregnant women had significantly fewer hospitalizations for dislocations, fractures, poisoning, sprains, and intracranial injuries, and more hospitalizations for contusions and internal injuries. Based on limited information about external causes of injury, pregnant women had significantly fewer hospitalizations for poisoning, drowning/suffocation, and suicide attempts than all women 15-44 years of age. CONCLUSIONS: Many hospitalizations of pregnant women are for relatively minor injuries requiring a short duration of stay, possibly to gauge the impact of the injury on the mother and the fetus. Since most pregnant women receive at least some medical care during pregnancy, prenatal visits represent an ideal time to implement strategies to prevent injuries.

Protein production: feeding the crystallographers and NMR spectroscopists.

Protein purification efforts for structural genomics will focus on automation for the readily-expressed proteins, and process development for the more difficult ones, such as membrane proteins. Thousands of proteins are expected to be produced in the next few years. The purified proteins will be valuable reagents for the entire research community.

COMPASS: a complex of proteins associated with a trithorax-related SET domain protein.

The trithorax genes encode an evolutionarily conserved family of proteins that function to maintain specific patterns of gene expression throughout cellular development. Members of this protein family contain a highly conserved 130- to 140-amino acid motif termed the SET domain. We report the purification and molecular identification of the subunits of a protein complex in the yeast Saccharomyces cerevisiae that includes the trithorax-related protein Set1. This protein complex, which we have named COMPASS (Complex Proteins Associated with Set1), consists of seven polypeptides ranging from 130 to 25 kDa. The same seven proteins were identified in COMPASS purified either by conventional biochemical chromatography or tandem-affinity tagging of the individual subunits of the complex. Null mutants missing any one of the six nonessential subunits of COMPASS grow more slowly than wild-type cells under normal conditions and demonstrate growth sensitivity to hydroxyurea. Furthermore, gene expression profiles of strains missing either of two nonessential subunits of COMPASS are altered in similar ways, suggesting these proteins have similar roles in gene expression in vivo. Molecular characterization of trithorax complexes will facilitate defining the role of this class of proteins in the regulation of gene expression and how their misregulation results in the development of human cancer.