Esperanto for histones: CENP-A, not CenH3, is the centromeric histone H3 variant.

The first centromeric protein identified in any species was CENP-A, a divergent member of the histone H3 family that was recognised by autoantibodies from patients with scleroderma-spectrum disease. It has recently been suggested to rename this protein CenH3. Here, we argue that the original name should be maintained both because it is the basis of a long established nomenclature for centromere proteins and because it avoids confusion due to the presence of canonical histone H3 at centromeres.

Molecular structures and interactions in the yeast kinetochore.

Kinetochores are the elaborate protein assemblies that attach chromosomes to spindle microtubules in mitosis and meiosis. The kinetochores of point-centromere yeast appear to represent an elementary module, which repeats a number of times in kinetochores assembled on regional centromeres. Structural analyses of the discrete protein subcomplexes that make up the budding-yeast kinetochore have begun to reveal principles of kinetochore architecture and to uncover molecular mechanisms underlying functions such as transmission of tension and establishment and maintenance of bipolar attachment. The centromeric DNA is probably wrapped into a compact organization, not only by a conserved, centromeric nucleosome, but also by interactions among various other DNA-bound kinetochore components. The rod-like, heterotetrameric Ndc80 complex, roughly 600 Å long, appears to extend from the DNA-proximal assembly to the plus end of a microtubule, to which one end of the complex is known to bind. Ongoing structural studies will clarify the roles of a number of other well-defined complexes.

A UK consensus on the management of the bladder in multiple sclerosis.

Bladder symptoms in multiple sclerosis (MS) are common and distressing but also highly amenable to treatment. A meeting of stakeholders involved in patients' continence care, including neurologists, urologists, primary care, MS nurses and nursing groups was recently convened to formulate a UK consensus for management. National Institute for Health and Clinical Excellence (NICE) criteria were used for producing recommendations based on a review of the literature and expert opinion. It was agreed that in the majority of cases, successful management could be based on a simple algorithm which includes using reagent sticks to test for urine infection and measurement of the post micturition residual urine volume. This is in contrast with published guidelines from other countries which recommend cystometry. Throughout the course of their disease, patients should be offered appropriate management options for treatment of incontinence, the mainstay of which is antimuscarinic medications, in combination, if necessary, with clean intermittent self-catheterisation. The evidence for other measures, including physiotherapy, alternative strategies aimed at improving bladder emptying, other medications and detrusor injections of botulinum toxin A was reviewed. The management of urinary tract infections as well as the bladder problems as part of severe disability were discussed and recommendations agreed.

A UK consensus on the management of the bladder in multiple sclerosis.

Bladder symptoms in multiple sclerosis (MS) are common and distressing but also highly amenable to treatment. A meeting of stakeholders involved in patients' continence care, including neurologists, urologists, primary care, MS nurses and nursing groups was recently convened to formulate a UK consensus for management. National Institute for Health and Clinical Excellence (NICE) criteria were used for producing recommendations based on a review of the literature and expert opinion. It was agreed that in the majority of cases, successful management could be based on a simple algorithm which includes using reagent sticks to test for urine infection and measurement of the post micturition residual urine volume. This is in contrast with published guidelines from other countries which recommend cystometry. Throughout the course of their disease, patients should be offered appropriate management options for treatment of incontinence, the mainstay of which is antimuscarinic medications, in combination, if necessary, with clean intermittent self-catheterisation. The evidence for other measures, including physiotherapy, alternative strategies aimed at improving bladder emptying, other medications and detrusor injections of botulinum toxin A was reviewed. The management of urinary tract infections as well as the bladder problems as part of severe disability were discussed and recommendations agreed.

Structural and functional dissection of Mif2p, a conserved DNA-binding kinetochore protein.

Mif2p is the budding-yeast orthologue of the mammalian centromere-binding protein CENP-C. We have mapped domains of Saccharomyces cerevisiae Mif2p and studied the phenotyptic consequences of their deletion. Using chromatin immunoprecipitation (ChIP) and electrophoretic mobility shift assays, we have further shown that Mif2p binds in the CDEIII region of the budding-yeast centromere, probably in close spatial association with Ndc10p. Moreover, ChIP experiments show that Mif2p recruits to yeast kinetochores a substantial subset of inner and outer kinetochore proteins, but not the Ndc80 or Spc105 complexes. We have determined the crystal structure of the C-terminal, dimerization domain of Mif2p. It has a "cupin" fold, extremely similar both in polypeptide chain conformation and in dimer geometry to the dimerization domain of a bacterial transcription factor. The Mif2p dimer seems to be part of an enhanceosome-like structure that nucleates kinetochore assembly in budding yeast.

Renal scarring in spinal cord injury: a progressive process?

STUDY DESIGN: A retrospective analysis. OBJECTIVES: To examine the natural history of renal scarring in the spinal cord injured population. SETTING: United Kingdom. METHODS: All spinal cord injured patients with renal scars at our establishment were considered eligible. A total of 27 patients with renal scars were identified. No patient had renal scarring at presentation on radiological imaging. All patients had annual renal imaging with a mean follow up period of 19.1 years. The presence of new scars was considered as evidence of progression. RESULTS: In all, 59% of kidneys developed renal scars with a mean time interval between spinal injury and renal scar development of 13 years. Of these kidneys with scars, only 15.6% demonstrated progression of the scarring process. There were no deaths due to renal causes. CONCLUSION: The aetiology of renal scarring is multifactorial. The findings of this study suggest that renal scarring in the spinal cord injured population is predominantly a nonprogressive process once a scar has developed. This is in concordance with the belief that renal scarring in the paediatric population with vesicoureteric reflux is also a stable, nonprogressive process.

Atraumatic retroperitoneal haemorrhage in a hydronephrotic kidney secondary to transitional cell carcinoma.

Retroperitoneal haemorrhage due to rupture of a hydronephrotic kidney has been described previously. There have only been two previous cases reporting retroperitoneal haemorrhage secondary to transitional cell carcinoma. We report two cases of spontaneous retroperitoneal haemorrhage in grossly hydronephrotic kidneys which had extensive transitional cell carcinoma present in the renal pelvis.

Bladder cancer in patients with spinal cord injuries.

OBJECTIVE: To evaluate the age-standardized incidence rate of bladder cancer in patients with spinal cord injury (SCI) and the overall risk for this population. PATIENTS AND METHODS: We reviewed 1334 patients with SCI whose dates of SCI, or first attendance at our centre, were between 1940 and 1998. The length of follow-up was calculated for each patient and age-specific incidence rates of bladder cancer calculated using 5-year age bands. This was used to calculate the overall incidence rate, using direct standardization with the European standard population. The cancers were analysed histochemically to characterize the phenotype. RESULTS: The 1324 patients contributed a total of 12 444 person-years of follow-up. There were four cases of bladder cancer, giving an age-standardized incidence rate of 30.7 per 100 000 person-years. Histochemistry showed areas were positive for cytokeratin 14, which was also positive in the undifferentiated areas. Immunohistochemical staining was positive for cytokeratin 14 and consistently negative for cytokeratin 20, suggesting a pure squamous phenotype. CONCLUSIONS: The age-standardized incidence of invasive bladder cancer in patients in our SCI unit is not statistically different from that of the general population. However, the incidence of invasive bladder cancer in the present study appears to be lower than that reported in other series. Histochemical analysis confirmed a squamous cell phenotype in these tumours.

A study of the morbidity, mortality and long-term survival following radical cystectomy and radical radiotherapy in the treatment of invasive bladder cancer in Yorkshire.

OBJECTIVES: To study the morbidity of radical cystectomy and radical radiotherapy in the treatment of patients with invasive carcinoma of the bladder and to report the long-term survival following these treatments. PATIENT AND METHODS: 398 patients with invasive carcinoma of the bladder treated between 1993 and 1996 in the Yorkshire region were studied. Of 398 patients studied, 302 patients received radical radiotherapy and 96 underwent radical cystectomy. A retrospective review of patients' case notes was performed to construct a highly detailed database. Crude estimates of survival differences were derived using Kaplan-Meier methods. Log-rank tests (or, where appropriate, Wilcoxon tests) were used to test for the equality of these survivor functions. These functions were produced as all-cause survival. The proportional hazards regression modelling was used to assess the impact of definitive treatment on survival. A backwards-stepwise approach was used to derive a final predictive model of survival, with likelihood ratio tests to assess the statistical significance of variables to be included in the model. RESULTS: The patients undergoing radiotherapy were significantly older (mean age: 71 years versus 66 years), but no difference was identified in the distribution of American Society of Anaesthesiologists (ASA) grades in the two treatment groups. The stage distribution of cases in the treatment groups was not significantly different. Significant treatment delays were observed in both treatment groups. The median time from being seen in the clinic to transurethral resection of bladder tumour (TURBT) and subsequent radical treatment (cystectomy or radiotherapy) was 4.3 and 9 weeks, respectively. Age was the most significant independent factor accounting for treatment delays (p < 0.001). The 30-day and 3-month treatment-associated mortality for radical cystectomy and radiotherapy was 3.1% and 8.3% and 0.3% and 1.65%. Of the patients who received radiotherapy, 57 (18.8%) were subsequently subjected to a salvage cystectomy. For these 57 patients, 30-day and 3-month mortality after the salvage cystectomy were 8.8% and 15.7%. Gastrointestinal complications were the major source of early morbidity after primary and salvage cystectomy. Bowel leakage occurred in 3% following radical and 8.7% after salvage cystectomy. Bowel complications (leakage and obstruction) were the major cause of death following salvage cystectomy. No specific cause was predominant in those undergoing radical cystectomy with intestinal anastomotic leakage and urinary leakage accounting for one death each. Exacerbation of co-morbid conditions accounted for the remaining causes of mortality. Urinary leakage occurred in 4% following both forms of cystectomy. Recurrent pyelonephritis and intestinal obstruction were responsible for the majority of complications in the follow-up period. Bladder and gastrointestinal complications accounted for the majority of complications following radical radiotherapy. Some degree of irritative bladder and rectal were noted commonly. Severe bladder problems, which rendered the bladder non-functional or required surgical correction, occurred in 6.3% of patients. 2.3% of patients underwent surgery for bowel obstruction related to radiotherapy induced bowel strictures. Following radiotherapy, 43.6% of patients had a recurrence in the bladder at varying intervals post-treatment. Of these, 40% had > or =T2 disease. The 5-year survival following radiotherapy (with or without salvage cystectomy) was 37.4% while 36.5% of patients were alive 5 years after radical cystectomy. There was no statistically significant difference in the overall 5-year survival figures between the two primary treatments. Tumour stage, ASA grade and sex were the only independent predictors of 5-year survival on multivariate analysis. CONCLUSIONS: This retrospective regional study shows that there is no significant difference in the 5-year survival of patients with invasive bladder cancer treated with either radical radiotherapy or radical cystectomy. All forms of radical treatment for bladder cancer are associated with a significant treatment-associated morbidity and mortality. Gastrointestinal complications were responsible for the majority of complications. The treatment-associated mortality at 3 months was two- or three-fold higher than the 30-day mortality; emphasising its importance as an indicator of the true risks of cystectomy. The clinical T stage, the sex and the ASA grade of the patient were the only independent predictors of survival. The data in this series suggests that radical radiotherapy and radical cystectomy should be both considered as valid primary treatment options for the management of invasive bladder cancer.

A small domain of CBP/p300 binds diverse proteins: solution structure and functional studies.

The transcriptional coactivators CBP and p300 are critical regulators of metazoan gene expression. They associate with many different DNA-bound transcription factors through small, conserved domains. We have identified a compactly folded 46 residue domain in CBP and p300, the IRF-3 binding domain (IBiD), and we have determined its structure by NMR. It has a helical framework containing an apparently flexible polyglutamine loop that participates in ligand binding. Spectroscopic data indicate that induced folding accompanies association of IBiD with its partners, which exhibit no evident sequence similarities. We demonstrate the significance both in vitro and in vivo of interactions between IBiD and a number of diverse partners. Thus, IBiD is an important contributor to signal integration by CBP and p300.

The stoichiometry of trimeric SIV glycoprotein interaction with CD4 differs from that of anti-envelope antibody Fab fragments.

Human and simian immunodeficiency viruses infect host lymphoid cells by binding CD4 molecules via their gp160 envelope glycoproteins. Biochemical studies on recombinant SIVmac32H (pJ5) envelope ectodomain gp140 precursor protein show that the envelope is a trimer. Using size exclusion chromatography, quantitative amino acid analysis, analytical ultracentrifugation, and CD4-based competition assay, we demonstrate that the stoichiometry of CD4 receptor-oligomeric envelope interaction is 1:1. By contrast, Fab fragments of both neutralizing and non-neutralizing monoclonal antibodies bind at a 3:1 ratio. Thus, despite displaying equivalent CD4 binding sites on each of the three gp140 protomers within an uncleaved trimer, only one site binds the soluble 4-domain human CD4 extracellular segment. The anti-cooperativity and the faster k(off) of gp140 trimer:CD4 versus gp120 monomer:CD4 interaction suggest that CD4-induced conformational change is impeded in the intact envelope. The implications of these findings for immunity against human immunodeficiency virus and simian immunodeficiency virus are discussed.

Proteolysis of monomeric recombinant rotavirus VP4 yields an oligomeric VP5* core.

Rotavirus particles are activated for cell entry by trypsin cleavage of the outer capsid spike protein, VP4, into a hemagglutinin, VP8*, and a membrane penetration protein, VP5*. We have purified rhesus rotavirus VP4, expressed in baculovirus-infected insect cells. Purified VP4 is a soluble, elongated monomer, as determined by analytical ultracentrifugation. Trypsin cleaves purified VP4 at a number of sites that are protected on the virion and yields a heterogeneous group of protease-resistant cores of VP5*. The most abundant tryptic VP5* core is trimmed past the N terminus associated with activation for virus entry into cells. Sequential digestion of purified VP4 with chymotrypsin and trypsin generates homogeneous VP8* and VP5* cores (VP8CT and VP5CT, respectively), which have the authentic trypsin cleavages in the activation region. VP8CT is a soluble monomer composed primarily of beta-sheets. VP5CT forms sodium dodecyl sulfate-resistant dimers. These results suggest that trypsinization of rotavirus particles triggers a rearrangement in the VP5* region of VP4 to yield the dimeric spikes observed in icosahedral image reconstructions from electron cryomicroscopy of trypsinized rotavirus virions. The solubility of VP5CT and of trypsinized rotavirus particles suggests that the trypsin-triggered conformational change primes VP4 for a subsequent rearrangement that accomplishes membrane penetration. The domains of VP4 defined by protease analysis contain all mapped neutralizing epitopes, sialic acid binding residues, the heptad repeat region, and the membrane permeabilization region. This biochemical analysis of VP4 provides sequence-specific structural information that complements electron cryomicroscopy data and defines targets and strategies for atomic-resolution structural studies.

Molecular organization of a recombinant subviral particle from tick-borne encephalitis virus.

The tick-borne encephalitis (TBE) flavivirus contains two transmembrane proteins, E and M. Coexpression of E and the M precursor (prM) leads to secretion of recombinant subviral particles (RSPs). In the most common form of these RSPs, analyzed at a 19 A resolution by cryo-electron microscopy (cryo-EM), 60 copies of E pack as dimers in a T = 1 icosahedral surface lattice (outer diameter, 315 A). Fitting the high-resolution structure of a soluble E fragment into the RSP density defines interaction sites between E dimers, positions M relative to E, and allows assignment of transmembrane regions of E and M. Lateral interactions among the glycoproteins stabilize this capsidless particle; similar interactions probably contribute to assembly of virions. The structure suggests a picture for trimer association under fusion-inducing conditions.

The familiar and the unexpected in structures of icosahedral viruses.

Viruses were the first large macromolecular assemblages to be visualized at high resolution. New virus structures continue to challenge our understanding of specificity in protein-protein "recognition". The evolution of virus structures has been even more opportunistic than previously imagined.

Structure of the reovirus outer capsid and dsRNA-binding protein sigma3 at 1.8 A resolution.

The crystallographically determined structure of the reovirus outer capsid protein sigma3 reveals a two-lobed structure organized around a long central helix. The smaller of the two lobes includes a CCHC zinc-binding site. Residues that vary between strains and serotypes lie mainly on one surface of the protein; residues on the opposite surface are conserved. From a fit of this model to a reconstruction of the whole virion from electron cryomicroscopy, we propose that each sigma3 subunit is positioned with the small lobe anchoring it to the protein mu1 on the surface of the virion, and the large lobe, the site of initial cleavages during entry-related proteolytic disassembly, protruding outwards. The surface containing variable residues faces solvent. The crystallographic asymmetric unit contains two sigma3 subunits, tightly associated as a dimer. One broad surface of the dimer has a positively charged surface patch, which extends across the dyad. In infected cells, sigma3 binds dsRNA and inhibits the interferon response. The location and extent of the positively charged surface patch suggest that the dimer is the RNA-binding form of sigma3.

Papillomavirus capsid protein expression in Escherichia coli: purification and assembly of HPV11 and HPV16 L1.

The L1 major capsid proteins of human papillomavirus (HPV) types 11 and 16 were purified and analyzed for structural integrity and in vitro self-assembly. Proteins were expressed in Escherichia coli as glutathione-S-transferase-L1 (GST-L1) fusions and purified to near homogeneity as pentamers (equivalent to viral capsomeres), after thrombin cleavage from the GST moiety and removal of tightly associated GroEL protein. Sequences at the amino and carboxy termini contributing to formation of L1 pentamers and to in vitro capsid assembly were identified by deletion analysis. For both HPV11 and HPV16 L1, up to at least ten residues could be deleted from the amino terminus (Delta N10) and 30 residues from the carboxy terminus (Delta C30) without affecting pentamer formation. The HPV16 pentamers assembled into relatively regular, 72-pentamer shells ("virus-like particles" or VLPs) at low pH, with the exception of HPV16 L1 Delta N10, which assembled into a 12-pentamer, T=1 capsid (small VLP) under all conditions tested. The production of large quantities of assembly-competent L1, using the expression and purification protocol described here, has been useful for crystallographic analysis, and will be valuable for studies of virus-receptor interactions and potentially for vaccine design.

Purified recombinant rotavirus VP7 forms soluble, calcium-dependent trimers.

Rotavirus is a major cause of severe, dehydrating childhood diarrhea. VP7, the rotavirus outer capsid glycoprotein, is a target of protective antibodies and is responsible for the calcium-dependent uncoating of the virus during cell entry. We have purified, characterized, and crystallized recombinant rhesus rotavirus VP7, expressed in insect cells. A critical aspect of the purification is the elution of VP7 from a neutralizing monoclonal antibody column by EDTA. Gel filtration chromatography and equilibrium analytical ultracentrifugation demonstrate that, in the presence of calcium, purified VP7 trimerizes. Trimeric VP7 crystallizes into hexagonal plates. Preliminary X-ray analysis suggests that the crystal packing reproduces the hexagonal component of the icosahedral lattice of VP7 on triple-layered rotavirus particles. These data indicate that the rotavirus outer capsid assembles from calcium-dependent VP7 trimers and that dissociation of these trimers is the biochemical basis for EDTA-induced rotavirus uncoating and loss of VP7 neutralizing epitopes.