Increased concentration of high-mobility group box 1 protein in milk is related to the severity of bovine mastitis.

High-mobility group box 1 (HMGB1) protein is the major component of the nonhistone nuclear protein group and is involved in nucleosome stabilization and transcription regulation. HMGB1 has recently been focused on as a proinflammatory cytokine associated with various inflammatory diseases and as a target of anti-inflammatory therapy. Mastitis, a serious inflammatory disease of dairy cows, is caused by infection of the mammary gland and has detrimental effects on the quantity and quality of milk.

DNase gamma-dependent and -independent apoptotic DNA fragmentations in Ramos Burkitt's lymphoma cell line.

DNA fragmentation is a biochemical hallmark of apoptosis. Several endonucleases, including CAD/DFF40 and endonuclease G, are implicated in DNA fragmentation. DNase gamma has also been considered to be one of the enzymes involved, but its role in relation to CAD/DFF40 in apoptosis has not been fully elucidated.

Action of apoptotic endonuclease DNase gamma on naked DNA and chromatin substrates.

The internucleosomal cleavage of genomic DNA is a biochemical hallmark of apoptosis. DNase gamma, a Mg2+/Ca2+-dependent endonuclease, has been suggested to be one of the apoptotic endonucleases, but its biochemical characteristic has not been fully elucidated. Here, using recombinant DNase gamma, we showed that DNase gamma is a Mg2+/Ca2+-dependent single-stranded DNA nickase and has a high activity at low ionic strength.

Guanine is indispensable for immunoglobulin switch region RNA-DNA hybrid formation.

It is suggested that the formation of the switch (S) region RNA-DNA hybrid and the subsequent generation of higher-order chromatin structures including R-loop initiate a class switch recombination of the immunoglobulin gene. The primary factor of this recombination is the S-region derived noncoding RNA. However, the biochemical character of this guanine-rich (G-rich) transcript is poorly understood.

Atomic force microscopy analysis of rolling circle amplification of plasmid DNA.

Rolling circle amplification (RCA) of plasmid DNA using random hexamers and bacteriophage phi29 DNA polymerase is an increasingly applied technique for amplifying template DNA for DNA sequencing. We analyzed this RCA reaction at a single-molecular level by atomic force microscopy (AFM) and found that multibranched amplified products containing tandem repeats of a circle unit are formed within 1 h. We also used the RCA product of a GFP expression vector for the protein expression in cells, and found that the crude RCA product from one bacterial colony is sufficient for the GFP expression.

Molecular visualization of immunoglobulin switch region RNA/DNA complex by atomic force microscope.

Immunoglobulin heavy-chain (IgH) class switch recombination (CSR) is initiated by DNA breakage in the switch (S) region featuring tandem repetitive nucleotide sequences. Various studies have demonstrated that S-region transcription and splicing proceed to genomic recombination and are indispensable for CSR in vivo, although the precise molecular mechanism is largely unknown. Here, we show the novel physical property of the in vitro transcribed S-region RNA by direct visualization using an atomic force microscope (AFM).

RAG2 is down-regulated by cytoplasmic sequestration and ubiquitin-dependent degradation.

Periodic accumulation and degradation of RAG2 (recombination-activating gene 2) protein controls the cell-cycle-dependent V(D)J recombination of lymphocyte antigen receptor genes. Here we show the molecular mechanism of RAG2 degradation. The RAG2 protein is translocated from the nucleus to the cytoplasm and degraded through the ubiquitin/proteasome system.