ZIB

Hits per page

hits 1 - 2 | 2 hits

Sorting

Electronic Resource

Outer membrane protein P6 of Haemophilus influenzae binds to its own gene (1992)

Sikkema, Daniel J. ; Nelson, M. Bud ; Apicella, Michael A. ; [et al.]

Oxford, UK : Blackwell Publishing Ltd

Molecular microbiology 6 (1992), S. 0

add to mindlist on the mindlist

Details

ISSN: 1365-2958

Source: Blackwell Publishing Journal Backfiles 1879-2005

Topics: Biology , Medicine

Notes: Outer membrane protein P6 is an important antigen expressed on the surface of all strains of Haemophilus influenzae. The predicted amino acid sequence of P6 contains a region of alpha helices that shares sequence identity with a family of helix-turn-helix DNA-binding proteins. A search for sequence-specific binding sites that resemble an operator region within the gene revealed a sequence with striking homology to the consensus operator sequence for lambda Cro and repressor. To test the hypothesis that P6 binds its own gene, purified P6 on nitrocellulose was probed with plasmid DNA containing the P6 gene. P6 bound the P6 gene in this Southwestern blot assay. To further test the observation, gel shift analysis was performed. Gel shift assays using a P6-specific monoclonal antibody demonstrated that P6 in crude cell extracts binds to the region of the gene containing the putative binding site. Competition with a synthetic oligonucleo-tide corresponding to the putative binding site inhibited binding of P6 to the P6 gene on nitrocellulose and in the gel shift assay. In addition, this oligonucleotide bound directly to P6 on nitrocellulose. Finally, DNase footprinting confirmed that P6 bound specifically to the same region of the P6 gene. These results indicate that P6 binds to a sequence-specific site within its own gene, suggesting that P6 regulates its own expression. This represents the first example of a Gram-negative outer membrane protein binding to its own gene and has potentially important implications as a mechanism for regulation of expression of outer membrane antigens.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1111/j.1365-2958.1992.tb01499.x

Permalink

Library	Location	Call Number	Volume/Issue/Year	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

Electronic Resource

B lymphocyte pathology in human colorectal cancer. Experimental and clinical therapeutic effects of partial B cell depletion (2000)

Barbera-Guillem, Emilio ; Nelson, M. Bud ; Barr, Barbara ; [et al.]

Springer

Cancer immunology immunotherapy 48 (2000), S. 541-549

add to mindlist on the mindlist

Details

ISSN: 1432-0851

Keywords: Key words Cancer therapy ; B cell depletion ; CD21 hyperexpression

Source: Springer Online Journal Archives 1860-2000

Topics: Medicine

Notes: Abstract Accumulating data are showing that the humoral immune response against tumors could favor tumor progression. However, no B lymphocyte pathology has been reported in cancer. Using anti-IgM Ab we nonspecifically depleted B cells in tumor-bearing mice, a treatment that resulted in significant reduction of tumor burden. We analyzed the B lymphocyte phenotype of abdominal lymph nodes and peripheral blood from advanced colon cancer patients by flow cytometry, and compared the B cell phenotype with that found in samples from normal donors. In both lymph nodes and peripheral blood of cancer patients, abnormal populations of B lymphocytes appeared that express an increased CD21 and/or sTn antigens on their cell surface. All patients showed a reduction of CD19+ cells. In a limited clinical test, we analyzed the effects of a partial B cell depletion with Rituximab. The treated patients did not develop any side-effects; the CD21-hyperpositive lymphocytes were reduced, but the proportion of sTn-positive lymphocytes remained unaffected. Apparent reduction of the tumor burden was reported in 50% of the patients when the treatment was ended.