Monoallelic expression of the interleukin-2 locus.

The lymphokine interleukin-2 (IL-2) is responsible for autocrine cell cycle progression and regulation of immune responses. Uncontrolled secretion of IL-2 results in adverse reactions ranging from anergy, to aberrant T cell activation, to autoimmunity. With the use of fluorescent in situ hybridization and single-cell polymerase chain reaction in cells with different IL-2 alleles, IL-2 expression in mature thymocytes and T cells was found to be tightly controlled by monoallelic expression. Because IL-2 is encoded at a nonimprinted autosomal locus, this result represents an unusual regulatory mode for controlling the precise expression of a single gene.

Escherichia coli RNA polymerase binding sites and transcription initiation sites in the transposon Tn3.

We have identified the Escherichia coli RNA polymerase-binding sites and the transcription initiation sites in the transposon Tn3. Results from nitrocellulose filter-binding assays indicate that there are two regions within Tn3 capable of forming stable binary complexes with RNA polymerase. The two regions are a 208-bp region containing the N-terminal coding sequence of the transposase (tnpA) and repressor (tnpR) genes, and a 332-bp region containing the N-terminal coding sequence for the beta-lactamase (bla) gene. DNase I footprint analysis of the 208-bp and 332-bp fragments further defined an extended region of protection, approx. 110 bp long, located between the transposase and repressor coding regions, and an 80-bp region of protection near the N-terminal coding sequence of the beta-lactamase gene. In vitro transcription studies with fragments containing these protected regions allowed us to determine the precise transcription initiation sites for the transposase, repressor, and beta-lactamase mRNAs. The transposase and repressor mRNAs are transcribed divergently and their transcription initiation sites are separated by 80 bp. The -35 homology regions for the transposase and repressor promoters are separated by 10 bp and the -10 homology region of the transposase promoter is coincident with the recombination site (res) for the site-specific recombinase activity (resolvase) of the repressor protein, which is required for resolution of Tn3 cointegrates. We discuss the significance of this complex divergently transcribed promoter region with respect to regulation of Tn3 transposition and we propose a model for coordinated regulation of the tnpA and tnpR genes. We also compare the Tn3 tnpA-tnpR intercistronic region with that of the closely related transposon gamma delta.

Susceptibility of Rocky Mountain bighorn sheep and domestic sheep to pneumonia induced by bighorn and domestic livestock strains of Pasteurella haemolytica.

Bighorn sheep were inoculated intratracheally with suspensions of nonhemolytic Pasteurella haemolytica biotype T (10(12) organisms) unique to wild bighorns, with beta-hemolytic P. haemolytica biotype T (10(12) organisms) isolated from clinically normal domestic sheep or intradermally with half a dose of a cattle vaccine containing P. haemolytica biotype A (10(5) organisms). The bighorn strain caused lobar necrotizing bronchopneumonia whereas both domestic livestock strains precipitated fatal septicemia and fibrinous bronchopneumonia. The serotypes given were T3, T4, T15 and A1 and these were recovered from lung lesions and other organs. In three trials, domestic sheep were inoculated intratracheally with suspensions of bighorn sheep pneumonic lungs, and two concentrations of the P. haemolytica bighorn strain (10(4) and 10(12) organisms). One of these sheep was inoculated intrabronchially. The domestic sheep experienced a transient fever and elevated white blood cell counts. After six days, none of the sheep had lung lesions and inoculated organisms could not be recovered. It is suggested that bighorn sheep are very susceptible to P. haemolytica from domestic livestock and should not be allowed in contact with sheep or cattle.

Experimental contact transmission of Pasteurella haemolytica from clinically normal domestic sheep causing pneumonia in Rocky Mountain bighorn sheep.

Two Rocky Mountain bighorn lambs (Ovis canadensis canadensis) were held in captivity for 120 days before being housed with two domestic sheep. The lambs were clinically normal and had no Pasteurella spp. on nasal swab cultures. The domestic sheep were known to carry Pasteurella haemolytica biotype A in the nasal passages. After being in close contact for 19 days. P. haemolytica biotype A was cultured from nasal swabs of one of the bighorn lambs. By 26 days, both bighorn sheep developed coughs, were anorectic and became lethargic and nasal swabs yielded P. haemolytica biotype T, serotype 10. Twenty-nine days after contact, the lambs were necropsied and found to have extensive fibrinous bronchopneumonia. From affected tissues pure cultures of beta-hemolytic P. haemolytica biotype T, serotype 10 were grown. Both domestic sheep remained clinically normal and had no gross or microscopic lesions, but they carried the same P. haemolytica serotype in their tonsils. Behavioural observations gave no indication of stress in the bighorn lambs.

Experimental infections of free-ranging Rocky Mountain bighorn sheep with lungworms (Protostrongylus spp.; Nematoda: Protostrongylidae).

Twelve free-ranging Rocky Mountain bighorn lambs (Ovis canadensis canadensis), each exposed experimentally to 125-1,000 infective third-stage larvae of Protostrongylus stilesi and P. rushi, shed significantly more first-stage larvae in their feces than did control lambs, but showed no clinical signs of illness and had equivalent summer and overwinter survival as control lambs. Two adult ewes, each exposed to 925 infective larvae, showed no increase in numbers of first-stage larvae in their feces; both survived at least 14 mo postexposure. Experimentally exposed lambs did not differ from control lambs in numbers of larvae in their feces in the following summer. Three experimental lambs had 313-402 adult P. stilesi and 0-97 adult P. rushi on necropsy; two control lambs had 255 and 270 P. stilesi and no P. rushi. The presence of these numbers of lungworms did not appear to be sufficient to precipitate lungworm pneumonia in bighorn lambs under the conditions of this study.

ATP-dependent specific binding of Tn3 transposase to Tn3 inverted repeats.

Transposons are discrete segments of DNA which are capable of moving from one site in a genome to many different sites. Tn3 is a prokaryotic transposon which is 4,957 base pairs (bp) long and encodes a transposase protein which is essential for transposition. We report here a simple method for purifying Tn3 transposase and demonstrate that the transposase protein binds specifically to the ends of the Tn3 transposon in an ATP-dependent manner. The transposase protein binds to linear double-stranded DNA both nonspecifically and specifically; the nonspecific DNA binding activity is sensitive to challenge with heparin. Site-specific DNA binding to the ends (inverted repeats) of Tn3 is observed only when binding is performed in the presence of ATP; this ATP-dependent site-specific DNA binding activity is resistant to heparin challenge. Our results indicate that ATP qualitatively alters the DNA binding activity of the transposase protein so that the protein is able to bind specifically to the ends of the Tn3 transposon.

Specific binding of transposase to terminal inverted repeats of transposable element Tn3.

Tn3 transposase, which is required for transposition of Tn3, has been purified by a low-ionic-strength-precipitation method. Using a nitrocellulose filter binding assay, we have shown that transposase binds to any restriction fragment. However, binding of the transposase to specific fragments containing the terminal inverted repeat sequences of Tn3 can be demonstrated by treatment of transposase-DNA complexes with heparin, which effectively removes the transposase bound to the other nonspecific fragments at pH 5-6. DNase I "footprinting" analysis showed that the transposase protects an inner 25-base-pair region of the 38-base-pair terminal inverted repeat sequence of Tn3. This protection is not dependent on pH. Interestingly, binding of the transposase to the inverted repeat sequences facilitates DNase I to nick at the end of the Tn3 sequence. It was also observed that the transposase protects the end regions of restriction fragments with a cohesive sequence at their 5' end or with a flush end from DNase I cleavage. The specific and nonspecific binding of transposase to DNA is ATP-independent.

Identification of a repeated sequence element required for efficient encapsidation of the adenovirus type 5 chromosome.

Adenovirus type 5 deletion mutants that lack portions of their cis-acting DNA encapsidation signal synthesized nearly normal levels of viral DNA and late polypeptides but failed to efficiently package the DNA into virus particles. A series of mutant viruses carrying small deletions were produced and used to identify a repeated element (AGTAAATTTGGGC and AGTAAGATTTGGCC) as a key component of the packaging signal. One copy of the repeat was sufficient to signal efficient packaging. The packaging domain could function near either end of the viral chromosome but was no longer active when moved several hundred base pairs toward the interior of the DNA molecule.

Localization of a gene coding for the phospholipase A2-L subtype (PLA2L) to human chromosome 8q24-qter.

Phospholipases A2 (PLA2) form an extended class of enzymes that play an important role in signal transduction. Phospholipase A2-like (PLA2L) belongs to the secreted forms of phospholipases A2, but constitutes a new subgroup. We have assigned the gene for this enzyme to human chromosome 8q24-qter using fluorescence in situ hybridization and radiation hybrid mapping techniques.

Human serum stimulates the production of G-CSF, IL-1, IL-6 and IL-8 by human peripheral blood leucocytes.

Human serum induces human peripheral blood leucocytes (PBL) to release an activity stimulating neutrophil colony formation (G-CSA) from human bone marrow cells. By titrating individual growth factors and using specific neutralizing antibodies we showed that: human serum contains very low levels of G-CSF which are by themselves insufficient to stimulate myeloid colony formation in primary human bone marrow cultures and cannot account for the serum releaser activity; that although no detectable levels of IL-1, IL-2, IL-3, IL-4, IL-6 or IL-8 are found in the serum, anti IL-1 antibodies partially block the release of G-CSA when added early during PBL incubation; that PBL incubated in the absence of serum for 2 d produce small amounts of IL-1, IL-6, IL-8 and G-CSF and this is increased 6-16 fold in the presence of human serum; and that the neutrophil colony-stimulating activity released by PBL incubated with human serum is G-CSF.

Induction of swelling, synovial hyperplasia and cartilage proteoglycan loss upon intra-articular injection of transforming growth factor beta-2 in the rabbit.

Transforming growth factor beta (TGF-beta) is a multifunctional homodimeric polypeptide with potent actions upon many target cells, including those of mesenchymal and haemopoietic lineage. The recent reports of high levels of the cytokine in rheumatoid synovium and synovial fluid, prompted this study into the effect of intra-articular injection of TGF beta-2 into rabbit knee-joints. Four daily injections of 1 microgram caused swelling, probably as a consequence of prostaglandin E2 production, synovial fibroblastic hyperplasia and a striking loss of femoral condyle proteoglycan. Using the polymerase chain reaction, no evidence could be obtained for the induction of interleukin-1 alpha gene expression in either synovial tissue or synovial fluid cells. These findings suggest that the TGF-beta present in the rheumatoid joint may contribute directly to the pathogenesis of rheumatoid arthritis.

Specific inhibition of the rat ligand-gated ion channel P2X3 function via methoxyethoxy-modified phosphorothioated antisense oligonucleotides.

P2X3 is one receptor of a family of seven ligand-gated ion channels responding to purines. Increasing evidence indicates its involvement in neuronal signaling and in pain. However, there is currently no selective inhibitor known for this subtype. In order to obtain such a specific inhibitor, a variety of antisense oligonucleotides (ASO) against rat P2X3 was tested, and dose-dependent, sequence-specific downregulation of the rat P2X3 receptor (expressed in a Chinese hamster ovary cell line [CHO-K1]) on the mRNA, protein, and functional levels was observed. Using real-time quantitative PCR, a dose-dependent downregulation of P2X3 mRNA by ASO, as compared with untreated and mismatch controls, was demonstrated. Subsequently, downregulation by the two most potent ASO was confirmed at the protein level by Western blot. Sequence specificity was shown by titration of mismatches to the original selected oligonucleotide, and this correlated with progressive loss of P2X3 inhibition. The functional response of the P2X3 receptor was examined using whole-cell voltage clamping. Upon application of 10 microM of a nonspecific agonist, alpha,beta-methylene-ATP (alphabeta meATP), pretreatment with increasing amounts of the most active ASO 5037 correlated with a decrease in depolarization. The ability to specifically downregulate the P2X3 receptor by ASO treatment will allow investigation of the biologic role of this receptor in neuronal tissues and eventually in in vivo models of chronic pain.

Poliovirus replication proteins: RNA sequence encoding P3-1b and the sites of proteolytic processing.

A partial amino-terminal amino acid sequence of each of the major proteins encoded by the replicase region (P3) of the poliovirus genome has been determined. A comparison of this sequence information with the amino acid sequence predicted from the RNA sequence that has been determined for the 3' region of the poliovirus genome has allowed us to locate precisely the proteolytic cleavage sites at which the initial polyprotein is processed to create the poliovirus products P3-1b (NCVP1b), P3-2 (NCVP2), P3-4b (NCVP4b), and P3-7c (NCVP7c). For each of these products, as well as for the small genome-linked protein VPg, proteolytic cleavage occurs between a glutamine and a glycine residue to create the amino terminus of each protein. This result suggests that a single proteinase may be responsible for all of these cleavages. The sequence data also allow the precise positioning of the genome-linked protein VPg within the precursor P3-1b just proximal to the amino terminus of polypeptide P3-2.

The effect of interleukin-1 on cytokine gene expression in cultured human articular chondrocytes analyzed by messenger RNA phenotyping.

OBJECTIVE: To investigate the pattern of cytokine gene expression in human articular chondrocytes in culture in response to interleukin-1 beta (IL-1 beta). The effect of serum and variations in culture conditions was also studied. METHODS: Messenger RNA was extracted from cells, reverse-transcribed to complementary DNA, and amplified by the polymerase chain reaction (PCR), using specific oligonucleotide primers. The PCR products were validated by restriction analysis with specific enzymes and by Southern blot analysis. RESULTS: In cultured articular chondrocytes, IL-1 beta, IL-1 alpha, granulocyte colony-stimulating factor (CSF), and granulocyte-macrophage CSF cytokine genes were expressed only after induction by IL-1 beta. However, IL-6, IL-8, and macrophage CSF genes were expressed constitutively. The expression of IL-1 beta was dose and time dependent. CONCLUSION: Using PCR, it was possible to demonstrate gene expression for several cytokines in human articular chondrocytes in culture. It was evident that some cytokine genes were expressed constitutively and some were inducible by IL-1 beta.

The SH3 domain of Src tyrosyl protein kinase interacts with the N-terminal splice region of the PDE4A cAMP-specific phosphodiesterase RPDE-6 (RNPDE4A5).

The PDE4A (type IV) cAMP-specific, rolipram-inhibited phosphodiesterase RPDE-6 (RNPDE4A5), when transiently expressed in COS7 cells, could be complexed with the v-Src-SH3 domain expressed as a glutathione S-transferase (GST) fusion protein. RPDE-6 did not interact with GST itself. This complex was not disrupted by treatment with high NaCl concentration together with Triton X-100. Interaction was apparently determined by the N-terminal splice region of RPDE-6, as the PDE4A splice variant RPDE-39, which differs from RPDE-6 at the extreme N-terminus, failed to associate with v-Src-SH3; met26RD1 (where RD1 is rat 'dunc-like' PDE), which has the N-terminal splice region deleted, failed to associate with v-Src-SH3, and the association of RPDE-6 and v-Src-SH3 was blocked by a fusion protein formed from the N-terminal splice region. RDPE-6 showed binding to GST fusion proteins of both the intact Src kinase and an SH2-SH3 construct but did not bind to the Src-SH2 domain or to the adaptor protein Grb-2. RPDE-6 could be co-immunoprecipitated from cytosol extracts of transfected cells by using anti-Src antiserum. RPDE-6 exhibited selectivity in binding to the SH3 domains of c-Abl, Crk, Csk, Lck, Lyn, Fyn and v-Src, with binding to the SH3 regions of the Src-related tyrosyl kinases Lyn and Fyn being the most effective. The binding of RPDE-6 to the SH3 domains of Crk, Csk and Lck led to a marked reduction in PDE activity, but no change was apparent in complexes with other species. Endogenous RPDE-6 from brain, but not endogenous RPDE-39 from testis, bound to the Src-SH3 domain. We suggest that the PDE4A splice variant RPDE-6 has a propensity for interaction with selective SH3 domains, in particular those from Src and the Src-related tyrosyl kinases Lyn and Fyn. This interaction seems to be governed by alternative splicing of the PDE4A gene, because RPDE-39, a splice variant that lacks the proline-rich N-terminal splice region of RPDE-6, does not interact with these SH3 domains. It is proposed that the binding site on RPDE-6 for SH3 domains lies within the unique first 102 residues of its N-terminal splice domain, where two motifs representing Class I SH3 binding sites with selectivity for Src kinase SH3 domains can be identified and one motif for a putative Class II SH3 binding site.

A genome survey indicates a possible susceptibility locus for bipolar disorder on chromosome 22.

Bipolar disorder or manic depressive illness is a major psychiatric disorder that is characterized by fluctuation between two abnormal mood states. Mania is accompanied by symptoms of euphoria, irritability, or excitation, whereas depression is associated with low mood and decreased motivation and energy. The etiology is currently unknown; however, numerous family, twin, and adoption studies have argued for a substantial genetic contribution. We have conducted a genome survey of bipolar disorder using 443 microsatellite markers in a set of 20 families from the general North American population to identify possible susceptibility loci. A maximum logarithm of odds score of 3.8 was obtained at D22S278 on 22q. Positive scores were found spanning a region of nearly 32 centimorgans (cM) on 22q, with a possible secondary peak at D22S419. Six other chromosomal regions yielded suggestive evidence for linkage: 3p21, 3q27, 5p15, 10q, 13q31-q34, and 21q22. The regions on 22q, 13q, and 10q have been implicated in studies of schizophrenia, suggesting the possible presence of susceptibility genes common to both disorders.