Expression of LAZ3/BCL6 in follicular center (FC) B cells of reactive lymph nodes and FC-derived non-Hodgkin lymphomas

A broiler chick bioassay was used to measure the effect of two inert digestibility markers on the determination of dietary AME. Diets contained 80% of either wheat or barley (with or without enzyme) and either chromic oxide at 0.5% or one of three levels of insoluble ash (0.5, 1.0, or 1.5%) as markers. The various cereal and marker diet combinations were consumed ad libitum (0 to 21 d) by two groups of 10 male broilers in each of two trials. The AME of each diet was determined by measuring the respective marker ratios between diet and excreta (collected for 24 h at 7 or 21 d) or ileal digesta collected at 21 d. Growth and feed conversion were measured on each group of birds between 0 and 21 d. There was no effect of marker on growth or feed efficiency. However, determination of AME of wheat- or barley-based diets with or without enzymes were affected by choice of marker and whether markers were measured in excreta (7 or 21 d) or ileal digesta. Chromic oxide was viewed as the least accurate method for determining AME, based on chronic oxide's inability to define AME differences between barley-based diets with and without enzymes, whereas insoluble ash clearly demonstrated improved AME of wheat- and barley-based diets with an enzyme. The optimum levels of insoluble ash for accuracy and repeatability were between 0.5 and 1.0%. The AME of the diets were, on average, 5% lower when determined with 7 vs 21 d excreta and 2.5% lower for ileal digesta than excreta collected at 21 d. It was concluded that identification of components that result in variability in AME levels of diets will be improved if a bioassay uses insoluble ash as a marker.     

Son of sevenless binds to the SH3 domain of src-type tyrosine kinase

Measurement of serum levels of ECP has been widely used for monitoring airway inflammation in bronchial asthma and recently been applied to measure anti-inflammatory effect of theophylline. However, reduced levels of ECP in theophylline-administered patients may express not only in vivo effect of theophylline but also in vitro effect after sampling because serum ECP measures released ECP during coagulation and theophylline has been reported to inhibit eosinophil degranulation in vitro. In order to answer the question, we tested whether theophylline added to blood after sampling reduces measured levels of serum ECP. Various concentrations of theophylline were added to SST tube, to which venous blood from atopic patients was drawn. Serum was, then, obtained by centrifugation after 15 min to 6 hours of incubation at room temperature. Theophylline significantly reduced serum ECP in a concentration-dependent manner. Percent reduction of ECP levels at 1 hour of incubation were 11.9%, 18.7%, 22.8%, and 51.7% at theophylline levels of 5, 12.5, 22.5, and 120 micrograms/ml, respectively. Kinetics of serum ECP release was also inhibited in the presence of theophylline. These results suggest that in vitro effect of theophylline on serum ECP levels should be considered when data of serum ECP in patients who take theophylline are interpreted.     

Identification of a domain of Axin that binds to the serine/threonine protein phosphatase 2A and a self-binding domain

Axin is a negative regulator of embryonic axis formation in vertebrates, which acts through a Wnt signal transduction pathway involving the serine/threonine kinase GSK-3 and beta-catenin. Axin has been shown to have distinct binding sites for GSK-3 and beta-catenin and to promote the phosphorylation of beta-catenin and its consequent degradation. This provides an explanation for the ability of Axin to inhibit signaling through beta-catenin. In addition, a more N-terminal region of Axin binds to adenomatous polyposis coli (APC), a tumor suppressor protein that also regulates levels of beta-catenin. Here, we report the results of a yeast two-hybrid screen for proteins that interact with the C-terminal third of Axin, a region in which no binding sites for other proteins have previously been identified. We found that Axin can bind to the catalytic subunit of the serine/threonine protein phosphatase 2A through a domain between amino acids 632 and 836. This interaction was confirmed by in vitro binding studies as well as by co-immunoprecipitation of epitope-tagged proteins expressed in cultured cells. Our results suggest that protein phosphatase 2A might interact with the Axin.APC.GSK-3.beta-catenin complex, where it could modulate the effect of GSK-3 on beta-catenin or other proteins in the complex. We also identified a region of Axin that may allow it to form dimers or multimers. Through two-hybrid and co-immunoprecipitation studies, we demonstrated that the C-terminal 100 amino acids of Axin could bind to the same region as other Axin molecules.     

Expression of the BCL6 gene in the pre- and postnatal mouse

Langerhans cell histiocytosis may be seen with goiter and histiocytic infiltration of the thyroid. We report a 2 1/2-year-old boy who had goiter and primary hypothyroidism develop, later had pulmonary disease, and died of neurologic involvement. Autopsy lesions suggested a transitional dendritic cell precursor of the epidermal Langerhans cell. Of the reported cases of Langerhans cell histiocytosis with goiter in children and adolescents, 82% were male when the relative incidence of Langerhans cell histiocytosis is two males to one female.     

A new type of cohesin domain that specifically binds the dockerin domain of the Clostridium thermocellum cellulosome-integrating protein CipA

The cellulosome-integrating protein CipA, which serves as a scaffolding protein for the cellulolytic complex produced by Clostridium thermocellum, comprises a COOH-terminal duplicated segment termed the dockerin domain. This paper reports the cloning and sequencing of a gene, termed sdbA (for scaffoldin dockerin binding), encoding a protein which specifically binds the dockerin domain of CipA. The sequenced fragment comprises an open reading frame of 1,893 nucleotides encoding a 631-amino-acid polypeptide, termed SdbA, with a calculated molecular mass of 68,577 kDa. SAA comprises an NH2-terminal leader peptide followed by three distinct regions. The NH2-terminal region is similar to the NH2-terminal repeats of C. thermocellum OlpB and ORF2p. The central region is rich in lysine and harbors a motif present in Streptococcus M proteins. The COOH-terminal region consists of a triplicated sequence present in several bacterial cell surface proteins. The NH2-terminal region of SdbA and a fusion protein carrying the first NH2-terminal repeat of OlpB were shown to bind the dockerin domain of CipA. Thus, a new type of cohesin domain, which is present in one, two, and four copies in SdbA, ORF2p, and OlpB, respectively, can be defined. Since OlpB and most likely SdbA and ORF2p are located in the cell envelope, the three proteins probably participate in anchoring CipA (and the cellulosome) to the cell surface.     

Rearrangements of the BCL6 gene and chromosome aberrations affecting 3q27 in 54 patients with non-Hodgkin's lymphoma

Chromosome aberrations affecting 3q27 are among the most frequent non-random abnormalities in non-Hodgkin's lymphomas (NHL), especially the diffuse, large cell type. Recently, an association between BCL6 rearrangement and frequent extranodal lesions, rare bone marrow infiltration and a favorable clinical outcome was reported. We performed molecular studies of the BCL6 gene in 54 patients with NHL. Twelve patients (22%) with rearranged BCL6 genes were selected for histological, clinical, molecular, and cytogenetic studies. Ten of these cases were diffuse, large cell type lymphoma, one a follicular lymphoma, and one a mantle cell lymphoma (MCL). All cases were of the B-cell type and this is the first time a rearranged BCL6 gene has been found in an MCL. Cytogenetic data for 10 cases were available and the partner sites of the 3q27 translocation were determined in 7 of 10 patients. These locations were variable, including 6p21.3, 9p22, and 14q11 in addition to the immunoglobulin loci 14q32 (IGH), 2p12 (IGK), and 22q11 (IGL). The heterogeneity in partner sites is distinct from other lymphoma subgroups and may suggest that the genetic events are not uniform among patients with BCL6 rearrangements.     

Interaction of the sarcin/ricin domain of 23 S ribosomal RNA with proteins L3 and L6

We investigated interaction of an RNA domain covering the target site of alpha-sarcin and ricin (sarcin/ricin domain) of Escherichia coli 23 S rRNA with ribosomal proteins. RNA fragments comprising residues 2630-2788 (Tox-1) and residues 2640-2774 (Tox-2) of 23 S rRNA were transcribed in vitro and used to analyze the binding proteins by gel shift and filter binding. Protein L6 bound to both Tox-1 (Kd: 0.31 microM) and Tox-2 (Kd: 0.18 microM), and L3 bound only to Tox-1 (Kd: 0.069 microM) in a solution containing 10 mM MgCl2 and 175 mM KCl at 0 degreesC. Footprinting studies were performed using the chemical probe dimethyl sulfate on full-length 23 S rRNA. Binding of L6 protected a single base, A-2757, and strongly enhanced reactivity of C-2752. A direct role of A-2757 in the L6 binding was verified by site-directed mutagenesis; replacements of A-2757 with G and C impaired the L6 binding. On the other hand, binding of L3 protected A-2632, A-2634, A-2635, A-2675, A-2726, A-2733, A-2749, and A-2750. Interestingly, binding of L6 and L3 together protected additional bases A-2657, A-2662, C-2666, and C-2667 in the sarcin/ricin loop, in addition to A-2740, A-2741, A-2748, A-2753, A-2764, A-2765, and A-2766 in the other stem-loop. This appears to be due to cooperative interaction of L3 and L6 with the RNA. The results are discussed with respect to conformational modulation of the sarcin/ricin domain by the protein binding.