Purification and properties of Drosophila heat shock activator protein

Regulation of the heat shock transcription factor Hsf1 in fungi: implications for temperature-dependent virulence traits

The impact of fungal pathogens on human health is devastating. For fungi and other pathogens, a key determinant of virulence is the capacity to thrive at host temperatures, with elevated temperature in the form of fever as a ubiquitous host response to defend against infection. A prominent feature of cells experiencing heat stress is the increased expression of heat shock proteins (Hsps) that play pivotal roles in the refolding of misfolded proteins in order to restore cellular homeostasis. Transcriptional activation of this heat shock response is orchestrated by the essential heat shock transcription factor, Hsf1. Although the influence of Hsf1 on cellular stress responses has been studied for decades, many aspects of its regulation and function remain largely enigmatic. In this review, we highlight our current understanding of how Hsf1 is regulated and activated in the model yeast Saccharomyces cerevisiae, and highlight exciting recent discoveries related to its diverse functions under both basal and stress conditions. Given that thermal adaption is a fundamental requirement for growth and virulence in fungal pathogens, we also compare and contrast Hsf1 activation and function in other fungal species with an emphasis on its role as a critical regulator of virulence traits.

Molecular mechanisms driving transcriptional stress responses

Proteotoxic stress, that is, stress caused by protein misfolding and aggregation, triggers the rapid and global reprogramming of transcription at genes and enhancers. Genome-wide assays that track transcriptionally engaged RNA polymerase II (Pol II) at nucleotide resolution have provided key insights into the underlying molecular mechanisms that regulate transcriptional responses to stress. In addition, recent kinetic analyses of transcriptional control under heat stress have shown how cells 'prewire' and rapidly execute genome-wide changes in transcription while concurrently becoming poised for recovery. The regulation of Pol II at genes and enhancers in response to heat stress is coupled to chromatin modification and compartmentalization, as well as to co-transcriptional RNA processing. These mechanistic features seem to apply broadly to other coordinated genome-regulatory responses.

A Telomeric Cluster of Antimony Resistance Genes on Chromosome 34 of Leishmania infantum

The mechanisms underlying the drug resistance of Leishmania spp. are manifold and not completely identified. Apart from the highly conserved multidrug resistance gene family known from higher eukaryotes, Leishmania spp. also possess genus-specific resistance marker genes. One of them, ARM58, was first identified in Leishmania braziliensis using a functional cloning approach, and its domain structure was characterized in L. infantum Here we report that L. infantum ARM58 is part of a gene cluster at the telomeric end of chromosome 34 also comprising the neighboring genes ARM56 and HSP23. We show that overexpression of all three genes can confer antimony resistance to intracellular amastigotes. Upon overexpression in L. donovani, ARM58 and ARM56 are secreted via exosomes, suggesting a scavenger/secretion mechanism of action. Using a combination of functional cloning and next-generation sequencing, we found that the gene cluster was selected only under antimonyl tartrate challenge and weakly under Cu(2+) challenge but not under sodium arsenite, Cd(2+), or miltefosine challenge. The selective advantage is less pronounced in intracellular amastigotes treated with the sodium stibogluconate, possibly due to the known macrophage-stimulatory activity of this drug, against which these resistance markers may not be active. Our data point to the specificity of these three genes for antimony resistance.

Heat shock factor binds to heat shock elements upstream of heat shock protein 70a and Samui genes to confer transcriptional activity in Bombyx mori diapause eggs exposed to 5°C

To understand the molecular mechanisms of how 5°C-incubation activates mRNA expression of Hsp70a and Samui genes in Bombyx mori diapause eggs, we first searched the 5'-upstream regions of the Hsp70a and Samui genes for heat shock elements (HSEs) and found two regions [Hsp70aHSE-1 (-95 to -58) and -2 (-145 to -121), and SamuiHSE-1 (-84 to -55) and -2 (-304 to -290)] corresponding to HSEs (repeats of nGAAn and/or nTTCn). We cloned four cDNAs encoding heat shock factor (HSF)-a2 (627 amino acids), -b (685 aa), -c (682 aa) and -d (705 aa), which were produced by alternative splicing. When we exposed diapause eggs to 5°C beginning at 2 day post-oviposition to break diapause, HSFd mRNA only increased after chilling for 6-8 days, a pattern very similar to those of Hsp70a and Samui mRNAs. To examine further whether HSFd binds to the respective HSEs, we carried out a gel shift assay using HSFd protein expressed in a cell-free system and the isolated HSEs; migration of the respective digoxigenin(DIG)-labeled HSE-1 and -2 of Hsp70a and Samui was retarded by addition of HSFd; the retarded bands disappeared after addition of the corresponding unlabeled HSE-1 and -2 as competitors, but were not affected by addition of the respective mutated unlabeled HSE-1 and -2. These results indicated that HSFd protein binds to the respective HSEs and may activate mRNA expression of Hsp70a and Samui genes upon exposure of diapause eggs to 5°C.

The RNA helicase Rm62 cooperates with SU(VAR)3-9 to re-silence active transcription in Drosophila melanogaster

Gene expression is highly dynamic and many genes show a wide range in expression over several orders of magnitude. This regulation is often mediated by sequence specific transcription factors. In addition, the tight packaging of DNA into chromatin can provide an additional layer of control resulting in a dynamic range of gene expression covering several orders of magnitude. During transcriptional activation, chromatin barriers have to be eliminated to allow an efficient progression of the RNA polymerase. This repressive chromatin structure has to be re-established quickly after it has been activated in order to tightly regulate gene activity. We show that the DExD/H box containing RNA helicase Rm62 is targeted to a site of rapid induction of transcription where it is responsible for an increased degree of methylation at H3K9 at the heat shock locus after removal of the heat shock stimulus. The RNA helicase interacts with the well-characterized histone methyltransferase SU(VAR)3-9 via its N-terminus, which provides a potential mechanism for the targeting of H3K9 methylation to highly regulated genes. The recruitment of SU(VAR)3-9 through interaction with a RNA helicase to a site of active transcription might be a general mechanism that allows an efficient silencing of highly regulated genes thereby enabling a cell to fine tune its gene activity over a wide range.

The stress of protein misfolding: from single cells to multicellular organisms

Organisms survive changes in the environment by altering their rates of metabolism, growth, and reproduction. At the same time, the system must ensure the stability and functionality of its macromolecules. Fluctuations in the environment are sensed by highly conserved stress responses and homeostatic mechanisms, and of these, the heat shock response (HSR) represents an essential response to acute and chronic proteotoxic damage. However, unlike the strategies employed to maintain the integrity of the genome, protection of the proteome must be tailored to accommodate the normal flux of nonnative proteins and the differences in protein composition between cells, and among individuals. Moreover, adult cells are likely to have significant differences in the rates of synthesis and clearance that are influenced by intrinsic errors in protein expression, genetic polymorphisms, and fluctuations in physiological and environmental conditions. Here, we will address how protein homeostasis (proteostasis) is achieved at the level of the cell and organism, and how the threshold of the stress response is set to detect and combat protein misfolding. For metazoans, the requirement for coordinated function and growth imposes additional constraints on the detection, signaling, and response to misfolding, and requires that the HSR is integrated into various aspects of organismal physiology, such as lifespan. This is achieved by hierarchical regulation of heat shock factor 1 (HSF1) by the metabolic state of the cell and centralized neuronal control that could allow optimal resource allocation between cells and tissues. We will examine how protein folding quality control mechanisms in individual cells may be integrated into a multicellular level of control, and further, even custom-designed to support individual variability and impose additional constraints on evolutionary adaptation.

Molecular chaperones antagonize proteotoxicity by differentially modulating protein aggregation pathways

The self-association of misfolded or damaged proteins into ordered amyloid-like aggregates characterizes numerous neurodegenerative disorders. Insoluble amyloid plaques are diagnostic of many disease states. Yet soluble, oligomeric intermediates in the aggregation pathway appear to represent the toxic culprit. Molecular chaperones regulate the fate of misfolded proteins and thereby influence their aggregation state. Chaperones conventionally antagonize aggregation of misfolded, disease proteins and assist in refolding or degradation pathways. Recent work suggests that chaperones may also suppress neurotoxicity by converting toxic, soluble oligomers into benign aggregates. Chaperones can therefore suppress or promote aggregation of disease proteins to ameliorate the proteotoxic accumulation of soluble, assembly intermediates.

Purification of sequence-specific DNA-binding proteins by affinity chromatography

The affinity chromatography procedure described in this unit uses DNA containing specific recognition sites for the desired protein that has been covalently linked to a solid support. Preparation of a DNA affinity resin, including cyanogen bromide (CNBr) activation of the agarose support, is described, and an alternate protocol provides a method to couple DNA to commercially available CNBr-activated Sepharose. A method for purification of crude synthetic oligonucleotides by gel electrophoresis prior to preparation of the affinity resin is also provided. A detailed protocol for the actual affinity chromatography procedure is described and a support protocol allows the investigator to determine the appropriate type and quantity of nonspecific competitor DNA that should be used in the procedure and its preparation. Parameters essential to the success of an affinity chromatography experiment are discussed in detail in the Commentary.

Genome-wide RNA polymerase II: not genes only!

RNA polymerase (Pol) II transcriptional regulation is an essential process for guiding eukaryotic gene expression. Early in vitro studies deciphered the essential steps for transcription, including recruitment, initiation, elongation and termination. Based on these findings, the idea emerged that Pol II should essentially be located on promoters or genic regions of transcribed genes. The development of in vivo localization protocols has enabled the investigation of genome-wide Pol II occupancy. Recent studies from yeast to human show that Pol II can be poised at the transcription start site or can be located outside of gene-coding regions, sometimes dependent on the growth or differentiation stage. These recent results regarding Pol II genomic location and transcription challenge our classical views of transcriptional regulation.

UV crosslinking of proteins to nucleic acids

Irradiation of protein-nucleic acid complexes with ultraviolet light causes covalent bonds to form between the nucleic acid and proteins that are in close contact with the nucleic acid. Thus, UV crosslinking may be used to selectively label DNA-binding proteins based on their specific interaction with a DNA recognition site. As a consequence of label transfer, the molecular weight of a DNA-binding protein in a crude mixture can be rapidly and reliably determined. This unit provides 3 protocols for executing DNA-protein crosslinking; one uses the halogenated thymidine analog bromodeoxyuridine (BrdU) to produce a DNA probe that is especially sensitive to UV-induced crosslinking. An alternate protocol describes crosslinking using a non-BrdU substituted probe, and another alternate protocol provides a method for in situ crosslinking.

Purification of sequence-specific DNA-binding proteins by affinity chromatography

Affinity chromatography is a very effective and straightforward means of purifying a protein based on its sequence-specific DNA-binding properties. The affinity chromatography procedure described in this unit uses DNA containing specific recognition sites for the desired protein that has been covalently linked to a solid support. The first basic protocol describes preparation of a DNA affinity resin, including cyanogen bromide (CNBr) activation of the agarose support. An provides a method to couple DNA to commercially available CNBr-activated Sepharose, and a support protocol describes how to purify crude synthetic oligonucleotides by gel electrophoresis prior to preparation of the affinity resin. The second basic protocol outlines the affinity chromatography procedure. A second support protocol describes determination of the appropriate type and quantity of nonspecific competitor DNA that should be used in the procedure and its preparation. Parameters essential to the success of an affinity chromatography experiment are discussed in detail in the Commentary.

New candidate genes for heat resistance in Drosophila melanogaster are regulated by HSF

The cellular heat stress response is well studied in Drosophila in respect to the role of heat shock proteins (Hsp). Hsps are molecular chaperones, highly expressed during and after exposure to numerous stress types. Hsps are all regulated by a common transcription factor, the heat shock factor (HSF), and it is known that HSF is controlling other, so far uncharacterised, heat-responsive genes. In this study, we investigate whether novel candidate genes for heat resistance, identified by microarray experiments, are regulated by HSF. The microarray experiments recently identified several strongly upregulated genes in response to a short, non-lethal heat treatment in Drosophila melanogaster. To test whether or not a subset of these genes are HSF-induced, we studied 11 currently unannotated genes using quantitative polymerase chain reaction on HSF mutant flies with a non-functional HSF at elevated temperatures. We found indication of HSF regulation in most of the studied genes, suggesting a role of these unknown genes in heat tolerance. Surprisingly, some of the genes seemed to be upregulated independent of HSF function. The high induction in response to heat, which mimics the expression profile of Hsps, implies a role in the cellular heat response of these genes as well.

Comparison of femtosecond laser and continuous wave UV sources for protein-nucleic acid crosslinking

Crosslinking proteins to the nucleic acids they bind affords stable access to otherwise transient regulatory interactions. Photochemical crosslinking provides an attractive alternative to formaldehyde-based protocols, but irradiation with conventional UV sources typically yields inadequate product amounts. Crosslinking with pulsed UV lasers has been heralded as a revolutionary technique to increase photochemical yield, but this method had only been tested on a few protein-nucleic acid complexes. To test the generality of the yield enhancement, we have investigated the benefits of using approximately 150 fs UV pulses to crosslink TATA-binding protein, glucocorticoid receptor and heat shock factor to oligonucleotides in vitro. For these proteins, we find that the quantum yields (and saturating yields) for forming crosslinks using the high-peak intensity femtosecond laser do not improve on those obtained with low-intensity continuous wave (CW) UV sources. The photodamage to the oligonucleotides and proteins also has comparable quantum yields. Measurements of the photochemical reaction yields of several small molecules selected to model the crosslinking reactions also exhibit nearly linear dependences on UV intensity instead of the previously predicted quadratic dependence. Unfortunately, these results disprove earlier assertions that femtosecond pulsed laser sources provide significant advantages over CW radiation for protein-nucleic acid crosslinking.

Heat shock factor 1 is a key regulator of the stress response in Chlamydomonas

We report here on the characterization of heat shock factor 1 (HSF1), encoded by one of two HSF genes identified in the genome of Chlamydomonas reinhardtii. Chlamydomonas HSF1 shares features characteristic of class A HSFs of higher plants. HSF1 is weakly expressed under non-stress conditions and rapidly induced by heat shock. Heat shock also resulted in hyperphosphorylation of HSF1, and the extent of phosphorylation correlated with the degree of induction of heat shock genes, suggesting a role for phosphorylation in HSF1 activation. HSF1, like HSFs in yeasts, forms high-molecular-weight complexes, presumably trimers, under non-stress, stress and recovery conditions. Immunoprecipitation of HSF1 under these conditions led to the identification of cytosolic HSP70A as a protein constitutively interacting with HSF1. Strains in which HSF1 was strongly under-expressed by RNAi were highly sensitive to heat stress. 14C-labelling of nuclear-encoded proteins under heat stress revealed that synthesis of members of the HSP100, HSP90, HSP70, HSP60 and small HSP families in the HSF1-RNAi strains was dramatically reduced or completely abolished. This correlated with a complete loss of HSP gene induction at the RNA level. These data suggest that HSF1 is a key regulator of the stress response in Chlamydomonas.

Chaperone regulation of the heat shock protein response

The heat shock protein response appears to be triggered primarily by nonnative proteins accumulating in a stressed cell and results in increased expression of heat shock proteins (HSPs). Many heat shock proteins prevent protein aggregation and participate in refolding or elimination of misfolded proteins in their capacity as chaperones. Even though several mechanisms exist to regulate the abundance of cytosolic and nuclear chaperones, activation of heat shock transcription factor 1 (HSF1) is an essential aspect of the heat shock protein response. HSPs and co-chaperones that are assembled into multichaperone complexes regulate HSF1 activity at different levels. HSP90-containing multichaperone complexes appear to be the most relevant repressors of HSF1 activity. Because HSP90-containing multichaperone complexes interact not only specifically with client proteins including HSF1 but also generically with nonnative proteins, the concentration of nonnative proteins influences assembly on HSF1 of HSP90-containing complexes that repress activation, and may play a role in inactivation, of the transcription factor. Proteins that are unable to achieve stable tertiary structures and remain chaperone substrates are targeted for proteasomal degradation through polyubiquitination by co-chaperone CHIP. CHIP can activate HSF1 to regulate the protein quality control system that balances protection and degradation of chaperone substrates.

The use of the Xenopus oocyte as a model system to analyze the expression and function of eukaryotic heat shock proteins

The analysis of the expression and function of heat shock protein (hsp) genes, a class of molecular chaperones, has been greatly aided by studies carried out with Xenopus oocytes. The large size of the oocyte facilitates microinjection of DNA, mRNA or protein, permits manual dissection of nuclei, and allows certain assays to be performed with single oocytes. These and other characteristics were useful in identifying the cis- and trans-acting factors involved in hsp gene transcription as well as the role of chaperones and co-chaperones in the repression and activation of heat shock factor. Xenopus oocytes were used to examine heat shock protein (HSP) molecular chaperone function as well as their involvement in intracellular trafficking, maturation, and secretion of protein. Possible new areas of research with this system include the role of membranes in the heat shock response, involvement of HSPs in viral replication and maturation, and in vivo NMR spectroscopy of microinjected HSPs.

The Drosophila P68 RNA helicase regulates transcriptional deactivation by promoting RNA release from chromatin

Terminating a gene's activity requires that pre-existing transcripts be matured or destroyed and that the local chromatin structure be returned to an inactive configuration. Here we show that the Drosophila homolog of the mammalian P68 RNA helicase plays a novel role in RNA export and gene deactivation. p68 mutations phenotypically resemble mutations in small bristles (sbr), the Drosophila homolog of the human mRNA export factor NXF1. Full-length hsp70 mRNA accumulates in the nucleus near its sites of transcription following heat shock of p68 homozygotes, and hsp70 gene shutdown is delayed. Unstressed mutant larvae show similar defects in transcript accumulation and gene repression at diverse loci, and we find that p68 mutations are allelic to Lighten-up, a known suppressor of position effect variegation. Our observations reveal a strong connection between transcript clearance and gene repression. P68 may be needed to rapidly remove transcripts from a gene before its activity can be shut down and its chromatin reset to an inactive state.

Regulation of RNA Polymerase II Transcription by Sequence-Specific DNA Binding Factors

In eukaryotes, transcription of the diverse array of tens of thousands of protein-coding genes is carried out by RNA polymerase II. The control of this process is predominantly mediated by a network of thousands of sequence-specific DNA binding transcription factors that interpret the genetic regulatory information, such as in transcriptional enhancers and promoters, and transmit the appropriate response to the RNA polymerase II transcriptional machinery. This review will describe some early advances in the discovery and characterization of the sequence-specific DNA binding transcription factors as well as some of the properties of these regulatory proteins.

Targeted disruption of the heat shock transcription factor (hsf)-2 gene results in increased embryonic lethality, neuronal defects, and reduced spermatogenesis

Heat shock transcription factors (Hsfs) are major transactivators of heat shock protein (Hsp) genes in the response to stress stimuli, but are also thought to be involved in embryonic development and spermatogenesis. Among the three known mammalian Hsfs, Hsf1 is recognized as the most effective transactivator of Hsps in response to thermal challenge, but the role of Hsf2 in regulation of genes under normal or increased stress conditions in vivo remains elusive. To study its physiological function in vivo, we generated mice deficient in hsf2 by gene targeting. We report here that hsf2(-/-) mice exhibit multiple phenotypes, including an increased prenatal lethality occurring between mid-gestation to birth, with fetal death probably due to central nervous system defects including collapse of the lateral ventricles and ventricular hemorrhages. Approximately 30% of hsf2(-/-) animals surviving to adulthood exhibited brain abnormalities characterized by marked dilation of the third and lateral ventricles. In addition, disruption of hsf2 resulted in reduced female fertility; however, despite ubiquitous expression in the testes and markedly reduced testis size and sperm count, only a small reduction in fertility was apparent in hsf2(-/-) male mice. Immunoblotting and gene expression microarray analysis of hsf2(-/-) embryos did not reveal reduced Hsp expression levels, indicating that the defects observed in hsf2(-/-) embryos may not result from disruption of Hsp expression. These findings suggest that hsf2 has a major function in controlling expression of genes important for embryonic development and maintenance of sperm production.

Transcription of cholesterol side-chain cleavage cytochrome P450 in the placenta: activating protein-2 assumes the role of steroidogenic factor-1 by binding to an overlapping promoter element

Progesterone is essential to the sustenance of pregnancy in humans and other mammals. From the second trimester on, the human placenta is the sole origin of de novo synthesized steroid hormones. In mice, placentation at midgestation is accompanied by a temporal rise of steroid hormone synthesis commencing in the giant cells of the mouse trophoblast. In doing so, the giant trophoblasts, as any other steroidogenic cell, express high levels of the key steroidogenic enzyme, cholesterol side-chain cleavage cytochrome P450 (P450scc). Because steroidogenic factor 1 (SF-1), the transcription factor required for expression of P450scc in the adrenals and the gonads, is not expressed in the placenta, we hypothesized that placenta-specific nuclear factor(s) (PNF) assumes the role of SF-1 by binding to the same promoter region that harbors the SF-1 recognition site in the P450scc gene. To address this possibility, we used SCC1, a well conserved proximal region in the P450scc genes (-60/-32 in the rat gene) to purify PNF from human term placenta. Sequencing of the purified PNF revealed that it is the alpha isoform of the human activating protein-2 (AP-2alpha). Specific antibodies tested in EMSA confirmed that AP-2alpha is the predominant isoform that binds SCC1 in the human placenta, whereas AP-2gamma is the only mouse placental protein that binds this oligonucleotide. Functional studies showed that coexpression of the rat P450scc promoter (-378/+8 CAT) and AP-2 isoforms (alpha or gamma) in human embryonic kidney 293 cells results in a marked activation of chloramphenicol acetyltransferase (CAT) transcription that is dependent on an intact AP-2 motif, GCCTTGAGC. This motif conforms with consensus sequences previously determined for binding of the AP-2 alpha and gamma isoforms. Mutations of the AP-2 element ablated binding of AP-2 to SCC1, as well as severely diminished the promoter activity in primary mouse giant trophoblasts and human choriocarcinoma JAR cells. Collectively, these studies suggest that expression of placental P450scc is governed by AP-2 factors that bind to a cis-element that largely overlaps the sequence required for recognition of SF-1 in other steroidogenic tissues.

Determination of the consensus binding sequence for the purified embryonic heat shock factor 2

Heat shock transcription factors (HSFs) are characterized by their ability, upon activation, to bind to heat shock response elements (HSE) present in the promoter of their target genes. HSE are composed of inverted repeats of the pentamer nGAAm. In this study, we compare the embryonic HSF2 protein, purified from F9 embryonal carcinoma cells tumor, and the in vitro synthesized HSF2. We show that the context of HSF2 synthesis influences its thermosensitivity and DNA-binding properties. Therefore, we determined the consensus binding sequence for the purified embryonic HSF2 by the technique of systematic evolution of ligands by exponential enrichment (SELEX). We show that embryonic HSF2 prefers sites containing three or four nGAAm inverted pentamers and that its optimal binding sequence contains the 8-mer palindromic core 5'-TTCTAGAA-3'. The consensus binding sequence for the embryonic HSF2 will be very helpful to identify new targets for this factor, during developmental and differentiation processes.

Semiquantitative reverse transcription-polymerase chain reaction with the Agilent 2100 Bioanalyzer

We have applied a method to monitor mRNA expression in a semiquantitative fashion on the Agilent 2100 Bioanalyzer. The method was originally described in 1994 by Wong et al. and referred to as the "primer-dropping" method. This polymerase chain reaction (PCR) technique uses multiple sets of primer pairs in a coamplification reaction that amplifies the target of interest within a predetermined range specific for each target. Separation, detection and quantification of PCR products were accomplished using the Agilent 2100 Bioanalyzer in conjunction with the DNA 500 and the DNA 1000 Lab-Chip kits for the detection of DNA fragments with a maximum size of 500 and 1000 bp, respectively. Using primers specific for the inducible form of hsp72 and primers for glyceraldehyde-3-phosphate dehydrogenase (GAPDH) as an internal standard we were able to rapidly monitor and quantify inducible hsp72-mRNA expression.

High-resolution localization of Drosophila Spt5 and Spt6 at heat shock genes in vivo: roles in promoter proximal pausing and transcription elongation

Recent studies have demonstrated roles for Spt4, Spt5, and Spt6 in the regulation of transcriptional elongation in both yeast and humans. Here, we show that Drosophila Spt5 and Spt6 colocalize at a large number of transcriptionally active chromosomal sites on polytene chromosomes and are rapidly recruited to endogenous and transgenic heat shock loci upon heat shock. Costaining with antibodies to Spt6 and to either the largest subunit of RNA polymerase II or cyclin T, a subunit of the elongation factor P-TEFb, reveals that all three factors have a similar distribution at sites of active transcription. Crosslinking and immunoprecipitation experiments show that Spt5 is present at uninduced heat shock gene promoters, and that upon heat shock, Spt5 and Spt6 associate with the 5' and 3' ends of heat shock genes. Spt6 is recruited within 2 minutes of a heat shock, similar to heat shock factor (HSF); moreover, this recruitment is dependent on HSF. These findings provide support for the roles of Spt5 in promoter-associated pausing and of Spt5 and Spt6 in transcriptional elongation in vivo.

Regional expression of heat shock protein 72 mRNA following mild and severe hypoxia in neonatal piglet brain

The present study examined the effect of hypoxia on expression of 72-kDa heat shock protein (hsp72) mRNA in the newborn brain. The studies were carried out in anesthetized and mechanically ventilated newborn piglets, age 3-5 days. Hypoxic insult was induced by decreasing the fraction of inspired oxygen (FiO2) from 21% to 6% or 10% for 1 h. Oxygen pressure in the microvasculature of the cortex (cortical pO2) was measured by oxygen dependent quenching of the phosphorescence of phosphor dissolved in blood. Following the two hours of normoxic recovery, regional expression of the 72-kDa heat shock protein (hsp72) mRNA was determined using in situ hybridization and autoradiography. Two grades of hypoxia were studied. Mild hypoxia (cortical pO2 = 10-30 mm Hg) induced the expression of hsp72 mRNA predominantly in the subcortical white matter. In individual animals of this group, the extent of expression varied from isolated regions to widespread involvement of the white matter. Severe hypoxia (cortical pO2 = 3-10 mm Hg) induced the expression of hsp72 mRNA in both white and gray matter regions, with strong expression occurring in the cerebral cortex of individual animals. The present results indicate that immature white matter is more sensitive than gray matter to the hypoxia induced expression of hsp72 mRNA. Further, increased expression of hsp72 mRNA may be an indicator of a pathologic degree of hypoxic stress, and the observed increase may indicate that in the newborn brain the immature white matter is particularly sensitive to injury by hypoxia-ischemia and reperfusion.

Purification and characterization of the serum amyloid A3 enhancer factor

Serum amyloid A (SAA) is a major acute-phase protein synthesized and secreted mainly by the liver. In response to acute inflammation, its expression may be induced up to 1000-fold, primarily as a result of a 200-fold increase in the rate of SAA gene transcription. We showed previously that cytokine-induced transcription of the SAA3 gene promoter requires a transcriptional enhancer that contains three functional elements: two CCAAT/enhancer-binding protein (C/EBP)-binding sites and a third site that interacts with a constitutively expressed transcription factor, SAA3 enhancer factor (SEF). Each of these binding sites as well as cooperation among their binding factors is necessary for maximum transcription activation by inflammatory cytokines. Deletion or site-specific mutations in the SEF-binding site drastically reduced SAA3 promoter activity, strongly suggesting that SEF is important in SAA3 promoter function. To further elucidate its role in the regulation of the SAA3 gene, we purified SEF from HeLa nuclear extracts to near homogeneity by using conventional liquid chromatography and DNA affinity chromatography. Ultraviolet cross-linking and Southwestern experiments indicated that SEF consisted of a single polypeptide with an apparent molecular mass of 65 kDa. Protein sequencing and antibody supershift experiments identified SEF as transcription factor LBP-1c/CP2/LSF. Cotransfection of SEF expression vector with SAA3-luciferase reporter resulted in approximately a 5-fold increase in luciferase activity. Interestingly, interleukin-1 treatment of SEF-transfected cells caused dramatic synergistic activation (31-fold) of the SAA3 promoter. In addition to its role in regulating SAA3 gene expression, we provide evidence that SEF could also bind in a sequence-specific manner to the promoters of the alpha(2)-macroglobulin and Aalpha-fibrinogen genes and to an intronic enhancer of the human Wilm's tumor 1 gene, suggesting a functional role in the regulation of these genes.

NF-kappaB involvement in the activation of primary adult T-cell leukemia cells and its clinical implications

The HTLV-I provirus-encoded Tax protein induces NF-kappaB in Tax-transfected Jurkat T cells or HTLVL-I- infected T cells in vitro. Tax induction of NF-kappaB is presumed to be involved in proliferation and activation of primary leukemia cells in vivo. Recent studies have demonstrated that NF-kappaB activities in human T cells are mediated by at least four c-Rel-related DNA binding proteins - p50, p55, p75 and p85. We examined the significance of NF-kappaB induction in primary adult T cell leukemia cells and the induction kinetics of each of the four NF-kappaB species. Marked NF-kappaB activity was detected using an electrophoretic mobility shift assay (EMSA) in the primary cells of patients with acute disease, but little activity was noted in the cells of chronic patients. NF-kappaB activity was enhanced in a time-dependent manner in acute type cells cultured with mitogen-free medium; there was no induction of activity in chronic type cells. UV crosslinking demonstrated all four species of NFkappaB complex - high levels of p50 and lower levels of p55 and p75, in acute type cells; chronic type cells showed only the p50. As a control, normal resting T cells similarly showed only p50; control cells showed little change in activity when cultured without mitogenic stimulation, analogous to chronic type ATL. Northern blotting revealed enhancement of c-rel (encoding p85) and KBFI (encoding p50 and p55) expression in acute type cells during culture, while there was no significant enhancement of mRNAs in chronic type ATL cells or unstimulated normal T cells. Northern blotting also revealed that Tax is upregulated at the mRNA level in acute- but not chronic-type cells during culture. Expression of c-rel and KBF1 mRNAs in acute type cells appeared to be related to Tax mRNA expression. These results suggest that Tax is capable of inducing nuclear expression of all four NF-kappaB species in primary ATL cells of acute type patients, with marked effects on p55, p75, and p85. Tax induction of NF-kappaB species is regulated, at least in part, at a pretranslational level involving increases in c-rel and KBF1 mRNA.

Multiple independent regulatory pathways control UBI4 expression after heat shock in Saccharomyces cerevisiae

Transcription of the polyubiquitin gene UBI4 of Saccharomyces cerevisiae is strongly induced by a variety of environmental stresses, such as heat shock, nutrient depletion and exposure to DNA-damaging agents. This transcriptional response of UBI4 is likely to be the primary mechanism for increasing the pool of ubiquitin for degradation of stress-damaged proteins. Deletion and promoter fusion studies of the 5' regulatory sequences indicated that two different elements, heat shock elements (HSEs) and stress response element (STREs), contributed independently to heat shock regulation of the UBI4 gene. In the absence of HSEs, STRE sequences localized to the intervals -264 to -238 and -215 to -183 were needed for stress control of transcription after heat shock. Site-directed mutagenesis of the STRE (AG4) at -252 to -248 abolished heat shock induction of UBI4 transcription. Northern analysis demonstrated that cells containing either a temperature-sensitive HSF or non-functional Msn2p/Msn4p transcription factors induced high levels of UBI4 transcripts after heat shock. In cells deficient in both heat stress pathways, heat-induced UBI4 transcript levels were considerably lower but not abolished, suggesting a role for another factor(s) in stress control of its expression.

Modeling transcriptional regulation using microinjection into Xenopus oocytes

Transcriptional regulation is a complex process that requires cooperation between specific DNA sequence elements, the DNA-binding proteins that bind to these sequences, the general transcriptional machinery, and chromatin. Oocyte microinjection offers a technique to study the integrated transcription process while still providing the opportunity to experimentally perturb this process. We describe here techniques for manipulating DNA templates and the protein complement of the oocyte to study multiple facets of transcriptional regulation. We present sample results showing that the GAL4-VP16 fusion activator is sensitive to distance in constructs containing only a minimal promoter, but can activate transcription at greater distances when proximal promoter elements are present.

Analysis of internal (n-1)mer deletion sequences in synthetic oligodeoxyribonucleotides by hybridization to an immobilized probe array

The purity of a drug substance can influence its toxicity and potency, so impurities must be specifically determined. In the case of synthetic oligodeoxyribonucleotide drugs, however, product complexity makes complete impurity speciation difficult. The goal of the present work was to develop a new analytical method for speciation of individual internal (n-1)mer impurities arising from formal nucleotide deletion in synthetic oligodeoxyribonucleotides. A complete series of oligodeoxyribonucleotide probes were designed, each complementary to an (n-1)mer deletion sequence of the drug in question. Glass plates were used as a solid support for individually immobilizing the entire probe array. The total mixture of internal (n-1) length impurities was isolated from a synthetic oligodeoxyribonucleotide by PAGE and labeled with 35S. Under stringently optimized conditions, only the perfectly sequence-matched oligodeoxyribonucleotide hybridized to each probe, while all other deletion sequences were removed by washing with buffer. The 35S signal intensity of the bound oligodeoxyribonucleotide was proportional to the concentration of each (n-1)mer deletion sequence in the analyte solution. This method has been applied to a number of synthetic phosphorothioate oligodeoxy-ribonucleotide lots and shown to be reliable for speciation and relative quantitation of the internal (n -1)mer deletion sequences present.

Heat- and cold-shock responses and temperature adaptations in subtropical and temperate species of Drosophila

Accumulation of Hsp70 mRNA was investigated with relation to heat and cold tolerance in adult males of three Drosophila species. The subtropical lowland species (D. watanabei) and the cool-temperate species (D. triauraria) were more tolerant to heat than the subtropical highland species (D. trapezifrons), and the cool-temperate species were much more tolerant to cold than the two subtropical species. Thus, heat and cold tolerance was related to temperature conditions in the habitats. The threshold temperatures for the induction of Hsp70 mRNA at heat and cold were higher in D. watanabei than in D. trapezifrons or D. triauraria, but were not different between the latter two species in spite of the difference in their heat and cold tolerance. In D. trapezifrons, exposures to 0 degrees C for 12h and 6 degrees C for 24h killed about 40% of individuals, but the former treatment induced Hsp70 mRNA while the latter one did not. Thus, the relation between the heat- and cold-shock responses and temperature tolerance was not rigid in the species studied. In D. triauraria, the threshold temperatures for the induction of Hsp70 mRNA at heat and cold were lower when reared at a lower temperature.

Metabolic oxidative stress-induced HSP70 gene expression is mediated through SAPK pathway. Role of Bcl-2 and c-Jun NH2-terminal kinase

In previous reports we demonstrated that glucose deprivation induces metabolic oxidative stress in drug-resistant human breast carcinoma MCF-7/ADR cells (Lee, Y. J., Galoforo, S. S., Berns, c. M., Chen, J. C., Davis, B. H., Swim, J. E., Corry, P. M., and Spitz, D. R. (1998) J. Biol. Chem. 273, 5294-5299). In the study described here, we investigated intracellular responses to metabolic oxidative stress. Northern blots show an increase in the level of HSP70 and HSP28 mRNA in cells exposed to glucose-free medium for 1 h. One- and two-dimensional polyacrylamide gel analyses confirmed that glucose deprivation induced a family of HSPs, particularly an inducible HSP70. Overexpression of bcl-2 suppressed glucose deprivation-induced HSP70 gene expression, heat shock transcription factor-heat shock element binding activity, as well as c-Jun NH2-terminal kinase (JNK1) activation. Expression of a dominant-negative mutant of JNK1 also suppressed glucose deprivation-induced JNK1 activation as well as HSP70 gene expression. Taken together, the stress-activated protein kinase signal transduction pathway is involved in glucose deprivation-induced heat shock gene expression.

Sequence-specific protein interaction with a transcriptional enhancer involved in the autoregulated expression of cAMP receptor 1 in Dictyostelium

Major stages of Dictyostelium development are regulated by secreted, extracellular cAMP through activation of a serpentine receptor family. During early development, oscillations of extracellular cAMP mobilize cells for aggregation; later, continuous exposure to higher extracellular cAMP concentrations downregulates early gene expression and promotes cytodifferentiation and cell-specific gene expression. The cAMP receptor 1 gene CAR1 has two promoters that are differentially responsive to these extracellular cAMP stimuli. The early CAR1 promoter is induced by nM pulses of cAMP, which in turn are generated by CAR1-dependent activation of adenylyl cyclase (AC). Higher, non-fluctuating concentrations of cAMP will adapt this AC stimulus-response, repress the activated early promoter and induce the dormant late promoter. We now identify a critical element of the pulse-induced CAR1 promoter and a nuclear factor with sequence-specific interaction. Mutation of four nucleotides within the element prevents both in vitro protein binding and in vivo expression of an otherwise fully active early CAR1 promoter and multimerization of the wild-type, but not mutant, sequence will confer cAMP regulation to a quiescent heterologous promoter. These cis and trans elements, thus, constitute a part of the molecular response to the cAMP transmembrane signal cascade that regulates early development of Dictyostelium.

IL-2-induced growth of CD8+ T cell prolymphocytic leukemia cells mediated by NF-kappaB induction and IL-2 receptor alpha expression

The binding of interleukin-2 (IL-2) to its receptor on normal T cells induces nuclear expression of nuclear factor kappaB (NF-kappaB), activation of the IL-2 receptor (IL-2R) alpha chain gene, and cell proliferation. In the present study, the role of IL-2R signaling in the growth of CD8+ T cell prolymphocytic leukemia (T-PLL) cells has been investigated. Flow cytometry revealed that primary leukemia cells from a patient with CD8+ T-PLL expressed IL-2Ralpha and beta chains, and the cells showed a proliferative response and an increase in IL-2Ralpha expression on culture with exogeneous IL-2. Northern blot analysis failed to detect IL-2 mRNA, suggesting that IL-2 may act in a paracrine manner in vivo. Electrophoretic mobility-shift assays revealed that recombinant IL-2 increased NF-kappaB binding activity in nuclear extracts of the leukemia cells, and Northern blot analysis showed that IL-2 increased the abundance of mRNAs encoding the NF-kappaB components c-Rel and KBF1 in these cells. IL-2 binding analysis demonstrated that IL-2 markedly increased the number of low affinity IL-2Rs on the leukemia cells, without an effect on the number of high-affinity IL-2Rs. These results show that IL-2 is capable of inducing the nuclear expression of NF-kappaB in primary CD8+ T-PLL cells, and that this effect is mediated, at least in part, at a pretranslational level.

A mathematical model of the hsp70 regulation in the cell

A mathematical model of the regulation process of the heat shock protein hsp70 in the cell is presented. The model describes the damaging effect of elevated temperature on proteins; the interaction of free hsp70 with injured proteins and its chaperone role in nascent protein translation; the relation between the amount of free hsp70 and the formation of the activated trimer form of the heat shock factor protein (HSF); the binding of activated HSF with the heat shock elements on the DNA; the transcription of mRNA of hsp70 and the synthesis of hsp70. The reaction of the model to a temporal rise in temperature shows an initial decline and a subsequent sharp rise to an ultimately increased level of free hsp70 in the cell. The response of the model to both a single and two consecutive heat shocks appears to closely resemble experimental data on hsp70 synthesis. This general agreement demonstrates the structure of the model to be sound and suitable as a basis for further modelling the complex tolerance mechanism of the cell.

The zinc finger protein CTCF binds to the APBbeta domain of the amyloid beta-protein precursor promoter. Evidence for a role in transcriptional activation

The promoter of the amyloid beta-protein precursor (APP) gene directs high levels of cell type-specific transcription with 94 base pairs 5' to the main transcriptional start site. An essential activator domain in this proximal APP promoter is a nuclear factor binding site designated as APBbeta. The recognition domain for the APBbeta binding factor is located between position -93 and -82 relative to the main transcriptional start site. The nuclear factor that binds to the APBbeta site was partially purified by multiple steps of ion exchange and hydroxyapatite chromatography. Based on UV cross-linking results, a protein with an apparent molecular mass of 140 kDa was selected as the putative APBbeta binding protein. After the final purification step consisting of preparative SDS-polyacrylamide gel electrophoresis, partial peptide sequences were obtained that completely matched the transcriptional factor CTCF. This protein is a known regulator of c-myc and lysozyme gene expression, and it binds to a variety of diverse DNA sequences. The binding of CTCF to the APBbeta domain was further established by competition with CTCF binding oligonucleotides in mobility shift electrophoresis. The identity was also confirmed by the observation that the APBbeta binding factor is recognized by antibodies against C- and N-terminal sequences of CTCF. In addition, oligonucleotide competition during in vitro transcription affirmed that CTCF acts as a transcriptional activator in the APP gene promoter.

Characterization of a specific region in the hepatitis B virus enhancer I for the efficient expression of X gene in the hepatic cell

Hepatitis B virus (HBV) enhancer I has been shown to consist of several cis-acting sequences for the HBV gene expression efficiently in certain types of cells. Transcriptional regulation of HBV X gene mediated by enhancer I might be one of the mechanisms by which HBV obtains hepatotropism. By mutagenesis analysis of enhancer I function in the enhancer I/X gene promoter complex, we characterized a specific transcriptional regulatory region (designated as a LSR element, nt 989-1030) of enhancer I for the X gene promoter by means of the transient transfection technique using hepatic and nonhepatic cells. Based on the analysis of protein factors interacting with the LSR element, liver-enriched transcriptional factors, HNF3 and HNF4 or retinoid X receptor alpha (RXR alpha), are probably implicated in the activity of enhancer I for the efficient expression of X gene through their interaction with the LSR element in the hepatic cell. Furthermore, the isolated LSR element was demonstrated to function alone as a specific cis-acting element and to be able to activate transcription from the X gene promoter efficiently in the hepatic cell in an orientation-independent manner.

Identification of CFDD (common regulatory factor for DNA replication and DREF genes) and role of its binding site in regulation of the proliferating cell nuclear antigen gene promoter

The Drosophila proliferating cell nuclear antigen (PCNA) gene promoter contains at least three transcriptional regulatory elements, the URE (upstream regulatory element), DRE (DNA replication-related element), and E2F recognition sites. In nuclear extracts of Drosophila Kc cells, we detected a novel protein factor(s), CFDD (common regulatory factor for DNA replication and DREF genes) that appeared to recognize two unique nucleotide sequences (5'-CGATA and 5'-CAATCA) and bind to three sites in the PCNA gene promoter. These sites were located at positions -84 to -77 (site 1), -100 to -93 (site 2) and -134 to -127 (site 3) with respect to the transcription initiation sites. Sites 2 and 3 overlapped with DRE and URE, respectively, and the 5'-CGATA matched with the reported recognition sequence of BEAF-32 (boundary element-associated factor of 32 kDa). Detailed analyses of CFDD recognition sequences and experiments with specific antibodies to DREF (DRE-binding factor) and BEAF-32 suggest that CFDD is different from DREF, UREF (URE-binding factor) and BEAF-32. A UV cross-linking experiment revealed that polypeptides of approximately 76 kDa in the nuclear extract interact directly with the CFDD site 1 sequence. Transient expression assays of chloramphenicol acetyltransferase (CAT) in Kc cells transfected with PCNA promoter-CAT fusion genes carrying mutations in CFDD site 1 and examination of lacZ expression from PCNA promoter-lacZ fusion genes carrying mutations in site 1, introduced into flies by germ line transformation, revealed that CFDD site 1 plays an important role for the promoter activity both in cultured cells and in living flies. In addition to the PCNA gene, multiple CFDD sites were found in promoters of the DNA polymerase alpha and DREF genes, and CFDD binding to the DREF promoter was confirmed. Therefore, CFDD may play important roles in regulation of Drosophila DNA replication-related genes.

Induction of nuclear factor kappa B/Rel nuclear activity in human peripheral blood T lymphocytes by anti-HLA class I monoclonal antibodies

Monoclonal antibodies against either monomorphic or polymorphic determinants of class I antigen induced in PBMC and highly purified T lymphocytes the nuclear activity of NF-kappa B/Rel complexes. These included both p50/p50 and p50/p65 dimers, recognized by specific antibodies in EMSA. The induced complexes were detectable in extracts of cells incubated with anti-class I monoclonal antibody (mAb) for 1.5 h; the induction was maximal at 5 h, persistent at 16 h and no longer observed at 40 h. The mAb failed to induce NF-kappa B/Rel nuclear activity in cells incubated in the presence of 3,4-dichloroisocoumarin, an inhibitor of I kappa B-alpha degradation. Together, these results suggest that class I triggering can induce the activity of NF-kappa B/Rel nuclear activity in peripheral blood T lymphocytes, thereby modulating the expression of genes regulated by these transcription factors.

Different thresholds in the responses of two heat shock transcription factors, HSF1 and HSF3

Avian cells express three HSF genes encoding a unique factor, HSF3, as well as homologues of mammalian HSF1 and HSF2. HSF1 is the major factor that mediates the heat shock signal in mammalian cells. We reported previously that cHSF3, as well as cHSF1, is activated by heat shock in chicken cells. In this study, we examined the functional differences between cHSF1 and cHSF3. Comparison of the heat-inducible DNA binding activity of cHSF1 with cHSF3 at various temperatures revealed that the latter was activated at higher temperatures than the former. At a mild heat shock, such as 41 degrees C, only cHSF1 was activated, whereas both cHSF1 and cHSF3 were activated following a severe heat shock at 45 degrees C. Heat-inducible nuclear translocation and trimerization were accompanied by DNA binding activity. We also observed that cHSF3 was activated by treating cells with higher concentrations of sodium arsenite compared to cHSF1. The DNA binding activity of cHSF3 by severe heat shock lasted for a longer period than that of cHSF1. Interestingly, the total amount of cHSF3 increased only upon severe heat shock, whereas that of HSF1 decreased. Substantial amounts of cHSF3 remained in the soluble fraction under severe heat shock, whereas cHSF1 rapidly moved to the insoluble fractions in that conditions. Comparison of transcriptional activity of the activation domains of cHSF1 and cHSF3 revealed that the activity of cHSF3 was as strong as that of cHSF1. These findings indicate that there are different thresholds for cHSF1 and cHSF3 and that cHSF3 is involved in the persistent and burst activation of stress genes upon severe stress in chicken cells. Pretreatment of cycloheximide elevated the threshold concentrations of arsenite of both factors. This suggests that denaturation of nascent polypeptides could be the first trigger for the activation of both factors, and the pathways for activation of cHSF1 and cHSF3 may be identical, or at least share some common mechanisms.

Regulation of human apolipoprotein A-I gene expression by gramoxone

To induce oxidative stress, HepG2 cells were exposed to a compound known as gramoxone. This compound undergoes a one-electron reduction to form a stable free radical which is capable of generating reactive oxygen species. We demonstrated that exposure of HepG2 cells to gramoxone (0.1 microM) resulted in a 2-fold decrease in apoA-I mRNA with no significant change in apoB and apoE mRNA levels. To examine if increased rates of mRNA degradation were responsible for the reduction in apoA-I mRNA levels, mRNA half-lives were measured in the presence of actinomycin D with and without gramoxone treatment. These studies revealed a 4-fold increase in the rate of apoA-I mRNA degradation in cells exposed to gramoxone. In similarly treated cells, nuclear run-off assays indicated that the transcription rate of the apoA-I gene was also increased 2-fold. Consistent with nuclear run-off assays, transient transfection experiments using a series of pGL2-derived luciferase reporter plasmids containing the human apoAI proximal promoter demonstrated that gramoxone treatment increased apoA-I promoter activity 2-fold. We have identified a potential "antioxidant response element" (ARE) in the apoA-I promoter region that may be responsible for the increase in apoA-I transcriptional activity by gramoxone. Gel mobility shift assays with an ARE oligonucleotide revealed increased levels of a specific protein-DNA complex that formed with nuclear extracts from gramoxone-treated cells. UV cross-linking experiments with the ARE and nuclear extracts from either untreated or gramoxone-treated cells detected proteins of approximately 100 and 115 kDa. When a single copy of the ARE was inserted upstream of the SV40 promoter in a luciferase reporter plasmid, a significant 2-fold induction in luciferase activity was observed in HepG2 cells in the presence of gramoxone. In contrast, a plasmid containing a mutant apoAI-ARE did not confer responsiveness to gramoxone. Furthermore, pGL2 (apoAI-250 mutant ARE), in which point mutations eliminated the ARE in the apoAI promoter, showed no increase in luciferase activity in response to gramoxone. Taken together, the data suggest that gramoxone affects apoA-I mRNA levels by both transcriptional and post-transcriptional mechanisms.

Induction of heat-shock protein (HSP72) in the cingulate and retrosplenial cortex by drugs that antagonize the effects of excitatory amino acids

To address the issue of the cytotoxicity of glutamate antagonists, we administered representative agents to rats and used HSP72 immunocytochemistry as a measure of neuronal injury in the brain. The doses studied spanned the reported neuroprotective range for each compound. Some, but not all, glutamate antagonists induce neuronal injury in the brain. The non-competitive NMDA antagonists (MK801 and dextrorphan) demonstrate maximum toxicity. Competitive NMDA antagonists (CGS 19755 and MDL 100,453) may or may not induce neuronal injury depending on the particular compound. The polyamine site (SL 82.0715-10) antagonist does not result in neuronal injury. Cingulate and retrosplenial cortex neurotoxicity is not a ubiquitous feature of neuroprotective agents that block excitotoxcity, but is limited to NMDA antagonists and may depend upon the duration and completeness of the blockade of the NMDA receptor.

Conserved elements in the 5' regulatory region of the amyloid precursor protein gene in primates

Oligonucleotides corresponding to conserved sites between the human and mouse amyloid precursor protein (APP) genes have been used to polymerase chain reaction (PCR) amplify and sequence the promoter region of the APP gene from chimpanzee, gorilla, orang-utan, papio and African green monkey. Several novel conserved potentially-regulatory sequences of the APP gene have been detected after alignment of the APP promoter sequences: an apolipoprotein E-B1 (APOE-B1) element at position -450, also present in the APOE gene, two activator protein-2 (AP-2) sites at positions -450 and -301 and an intermediate early-1 gene (IE1) site at position -280. These elements are conserved in all mammalian APP promoter sequences studied. Additionally a previously detected heat shock element (HSE) at position -317, and an activator protein-1 (AP-1) site at position -350 are also conserved. Knowledge of the essential regulatory elements at the APP gene constitute the basis for understanding its transcriptional control and subsequent model studies.