Fetal and newborn calf thymus as a source of chromatin proteins: purification of HMG-1 and HMG-2

HMGB1 in hormone-related cancer: a potential therapeutic target

High-mobility group box 1 (HMGB1) is a dynamic nuclear protein participating in transcription, chromatin remodelling, and DNA recombination and repair processes. Accumulating evidence indicates that its function now extends beyond the nucleus, notably its extracellular role in inflammation. HMGB1 is implicated as a late mediator of sepsis and is also believed to promote atherosclerosis and other inflammatory diseases such as rheumatoid arthritis and systemic lupus erythematosus. Interestingly, deregulation of HMGB1 is shown to be associated with the hallmarks of cancer development. Moreover, several clinical studies have shown that HMGB1 is a promising biomarker for a variety of cancer types. In this review, we provide novel insights into the role and mechanisms of HMGB1, in particular, to hormone-related cancers and its potential to serve as a therapeutic target.

A single-column chromatographic system for the analysis and preparation of high mobility group proteins 1 and 2 and other chromosomal proteins using nondenaturing solvents

One-step chromatography on a Mono S column allows the purification of high mobility group (HMG) proteins 1 and 2 under nondenaturing conditions. Chromatography of HMG1 and -2 on Mono S can be achieved with three of the most widely employed extraction techniques for chromosomal proteins, 0.35 M sodium chloride, 0.74 M perchloric acid, and 0.4 N sulfuric acid. In each case HMG1 and -2 are purified away from the other chromosomal proteins, histone H1, and core histones, and are resolved into both their reduced and oxidized forms. Additionally histone H1 and the core histones are fractionated on Mono S, thus the entire complement of chromosomal proteins can be analyzed in a single rapid chromatographic step.

Isolation and characterization of folded fragments released by Staphylococcal aureus proteinase from the non-histone chromosomal protein HMG-1

HMG-1 was isolated from newborn calf thymus without exposure to overt denaturing conditions. The purified protein was digested under several solvent conditions with the proteinase (endoproteinase GluC) from Staphylococcus aureus strain V8. We found that the preferred site of attack by the enzyme on HMG-1 was influenced markedly by ionic strength and temperature. In 0.35 M NaCl/50 mM Tris-phosphate (pH 7.8) at 37 degrees C, cleavage near the junction between the A and B domains is predominant, as previously reported by Carballo et al. (EMBO J. 2 (1983) 1759-1764). However, in 50 mM Tris-phosphate (pH 7.8) lacking NaCl and at 0 degrees C, cleavage between the B and C domains strongly predominates. Three major products of the digestions were purified and characterized. The fragment consisting of domains B and C was found by circular dichroism to contain a substantial amount of helix. This re-emphasizes the importance of avoiding overt denaturing conditions when working with members of the HMG-1 family.