We have determined to 2.6 A resolution the crystal structure of the thermosome, the archaeal group II chaperonin from T. acidophilum. The hexadecameric homolog of the eukaryotic chaperonin CCT/TRiC shows an (alphabeta)4(alphabeta)4 subunit assembly. Domain folds are homologous to GroEL but form a novel type of inter-ring contact. The domain arrangement resembles the GroEL-GroES cis-ring. Parts ...

Microtubules are hollow polymers of alphabeta-tubulin that show GTP-dependent assembly dynamics and comprise a critical part of the eukaryotic cytoskeleton. Initiation of new microtubules in vivo requires gamma-tubulin, organized as an oligomer within the 2.2-MDa gamma-tubulin ring complex (gamma-TuRC) of higher eukaryotes. Structural insight is lacking regarding gamma-tubulin, its oligomerizat...

Three photosynthetic complexes, light-harvesting complex 2 (LH2), light-harvesting complex 1 (LH1), and the reaction centre-light-harvesting complex 1 photounit (RC-LH1), were purified from a single species of a purple bacterium, Rhodobacter sphaeroides, and reconstituted into two-dimensional (2-D) crystals. Vesicular 2-D crystals of LH1 and RC-LH1 were imaged in negative stain and projection m...

The early systemic production of interferon (IFN)-alphabeta is an essential component of the antiviral host defense mechanisms, but is also thought to contribute to the toxic side effects accompanying gene therapy with adenoviral vectors. Here we investigated the IFN-alphabeta response to human adenoviruses (Ads) in mice. By comparing the responses of normal, myeloid (m)DC- and plasmacytoid (p)...

Thymic precursors expressing the pre-T cell receptor (TCR), the gammadeltaTCR, or the alphabetaTCR can all enter the CD4+ 8+ alphabeta lineage, albeit with different efficacy. Here it is shown that proliferation and differentiation of precursors with the different TCRs into alphabeta lineage cells require Notch signaling at the DN3 stage of thymic development. At the DN4 stage, Notch signaling ...

To determine the phenotypes of cytotoxic cells in channel catfish, clonal alloantigen-dependent leukocyte lines were established from mixed leukocyte cultures. Each clone was analyzed for expression of TCR alpha and beta genes by RT-PCR and for target cell specificity by 51Cr-release assay. Based on the above criteria, the following five different cell types were identified among the 19 clones ...

The study was undertaken to further elucidate a role of gonadal hormones in maintenance of normal thymocyte maturation and sexual dimorphism in the intrathymic T-cell development. Rats of both sexes were gonadectomized or sham-gonadectomized (controls) at age of 2 and 6 months, and 30 days later the thymus size, cellularity and thymocyte composition were evaluated. In both control and gonadecto...

The humoral immune response to Borrelia burgdorferi during persistent infection is critical to both protective and disease-resolving immunity. This study examined the role of B cells in the absence of T cells during these events, using mice with selected immune dysfunctions. At 6 weeks postinfection, an interval at which arthritis resolves in immunocompetent mice, arthritis severity was equival...