We analyzed the function of the downstream promoter element (DPE), a distinct 7-nucleotide core promoter element that is ∼30 nucleotides downstream of the transcription start site of many TATA-box-deficient (TATA-less) promoters in Drosophila. There is a strict requirement for spacing between the Inr and DPE motifs, as an increase or decrease of 3 nucleotides in the distance between the Inr and DPE causes a seven-to eightfold reduction in transcription as well as a significant reduction in the binding of purified TFIID. These results suggest a specific and somewhat rigid interaction of TFIID with the Inr and DPE sequences. Photo-cross-linking analysis of purified TFIID with a TATA-less DPE-containing promoter revealed specific cross-linking of dTAF II 60 and dTAF II 40 to the DPE, with a higher efficiency of cross-linking to dTAF II 60 than to dTAF II 40. These data, combined with the previously well-characterized interactions between the two TAFs and their homology to histones H4 and H3, suggest that a dTAF II 60-dTAF II 40 heterotetramer binds to the DPE. Human and Drosophila transcription factors exhibit essentially the same requirements for DPE sequence and for Inr-DPE spacing. In addition, the TATA-less promoter of the human interferon regulatory factor-1 (IRF-1) gene contains a DPE that is important for transcriptional activity both in vitro and in cultured cells. Hence, these studies provide evidence for a direct role of TAFs in basal transcription of TATA-less DPE-containing genes and collectively indicate that the DPE is, in many respects, a downstream counterpart to the TATA box that is present in Drosophila to humans. Transcription is centrally involved in an array of biological processes, which include growth, development, and response to external stimuli. In eukaryotes, protein-coding genes are transcribed by the RNA polymerase II transcriptional machinery, which comprises RNA polymerase II and other factors that are required for basal and regulated transcription. Transcription by RNA polymerase II is directed by cis-acting DNA sequences that typically consist of a core promoter along with regulatory elements, such as enhancers, that contain binding sites for sequence-specific transcriptional activator and/or repressor proteins. Thus, the study of both the trans-acting protein factors and the cis-acting DNA elements is necessary to gain a better understanding of the fundamental mechanisms by which genes are transcribed (for recent reviews, see Bjö rkland and
We describe the identification and characterization of a conserved downstream basal promoter element that is present in a subset of Drosophila TATA-box-deficient (TATA-Iess) promoters by using purified, epitope-tagged TFIID complex (eTFIID) from embryos of transgenic Drosophila. [Key Words: RNA polymerase II; in vitro transcription; core promoter; initiator element; TATA-box-binding protein; TBP-associated factors]
Acute respiratory infections caused by bacterial or viral pathogens are among the most common reasons for seeking medical care. Despite improvements in pathogen-based diagnostics, most patients receive inappropriate antibiotics. Host response biomarkers offer an alternative diagnostic approach to direct antimicrobial use. This observational, cohort study determined whether host gene expression patterns discriminate non-infectious from infectious illness, and bacterial from viral causes of acute respiratory infection in the acute care setting. Peripheral whole blood gene expression from 273 subjects with community-onset acute respiratory infection (ARI) or non-infectious illness as well as 44 healthy controls was measured using microarrays. Sparse logistic regression was used to develop classifiers for bacterial ARI (71 probes), viral ARI (33 probes), or a non-infectious cause of illness (26 probes). Overall accuracy was 87% (238/273 concordant with clinical adjudication), which was more accurate than procalcitonin (78%, p<0.03) and three published classifiers of bacterial vs. viral infection (78-83%). The classifiers developed here externally validated in five publicly available datasets (AUC 0.90-0.99). A sixth publically available dataset included twenty-five patients with co-identification of bacterial and viral pathogens. Applying the ARI classifiers defined four distinct groups: a host response to bacterial ARI; viral ARI; co-infection; and neither a bacterial nor viral response. These findings create an opportunity to develop and utilize host gene expression classifiers as diagnostic platforms to combat inappropriate antibiotic use and emerging antibiotic resistance.
In this large series of women with hereditary nonpolyposis colorectal cancer syndrome who developed 2 primary colorectal/gynecologic cancers, endometrial cancer/ovarian cancer was the "sentinel cancer," preceding the development of colon cancer, in half of the cases. Therefore, gynecologists and gynecologic oncologists play a pivotal role in the identification of women with hereditary nonpolyposis colorectal cancer syndrome.
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