Initial sequencing and analysis of the human genome

The human genome holds an extraordinary trove of information about human development, physiology, medicine and evolution. Here we report the results of an international collaboration to produce and make freely available a draft sequence of the human genome. We also present an initial analysis of the data, describing some of the insights that can be gleaned from the sequence.

The development of Assessment of SpondyloArthritis international Society classification criteria for axial spondyloarthritis (part II): validation and final selection

OBJECTIVE

To validate and refine two sets of candidate criteria for the classification/diagnosis of axial spondyloarthritis (SpA).

METHODS

All Assessment of SpondyloArthritis international Society (ASAS) members were invited to include consecutively new patients with chronic (> or =3 months) back pain of unknown origin that began before 45 years of age. The candidate criteria were first tested in the entire cohort of 649 patients from 25 centres, and then refined in a random selection of 40% of cases and thereafter validated in the remaining 60%.

RESULTS

Upon diagnostic work-up, axial SpA was diagnosed in 60.2% of the cohort. Of these, 70% did not fulfil modified New York criteria and, therefore, were classified as having "non-radiographic" axial SpA. Refinement of the candidate criteria resulted in new ASAS classification criteria that are defined as: the presence of sacroiliitis by radiography or by magnetic resonance imaging (MRI) plus at least one SpA feature ("imaging arm") or the presence of HLA-B27 plus at least two SpA features ("clinical arm"). The sensitivity and specificity of the entire set of the new criteria were 82.9% and 84.4%, and for the imaging arm alone 66.2% and 97.3%, respectively. The specificity of the new criteria was much better than that of the European Spondylarthropathy Study Group criteria modified for MRI (sensitivity 85.1%, specificity 65.1%) and slightly better than that of the modified Amor criteria (sensitivity 82.9, specificity 77.5%).

CONCLUSION

The new ASAS classification criteria for axial SpA can reliably classify patients for clinical studies and may help rheumatologists in clinical practice in diagnosing axial SpA in those with chronic back pain.

TRIAL REGISTRATION NUMBER

NCT00328068.

Regulation of hypoxia-inducible factor 1alpha is mediated by an O2-dependent degradation domain via the ubiquitin-proteasome pathway

Hypoxia induces a group of physiologically important genes such as erythropoietin and vascular endothelial growth factor. These genes are transcriptionally up-regulated by hypoxia-inducible factor 1 (HIF-1), a global regulator that belongs to the basic helix-loop-helix PAS family. Although HIF-1 is a heterodimer composed of alpha and beta subunits, its activity is primarily determined by hypoxia-induced stabilization of HIF-1alpha, which is otherwise rapidly degraded in oxygenated cells. We report the identification of an oxygen-dependent degradation (ODD) domain within HIF-1alpha that controls its degradation by the ubiquitin-proteasome pathway. The ODD domain consists of approximately 200 amino acid residues, located in the central region of HIF-1alpha. Because portions of the domain independently confer degradation of HIF-1alpha, deletion of this entire region is required to give rise to a stable HIF-1alpha, capable of heterodimerization, DNA-binding, and transactivation in the absence of hypoxic signaling. Conversely, the ODD domain alone confers oxygen-dependent instability when fused to a stable protein, Gal4. Hence, the ODD domain plays a pivotal role for regulating HIF-1 activity and thereby may provide a means of controlling gene expression by changes in oxygen tension.

Niemann-Pick C1 disease gene: homology to mediators of cholesterol homeostasis

Niemann-Pick type C (NP-C) disease, a fatal neurovisceral disorder, is characterized by lysosomal accumulation of low density lipoprotein (LDL)-derived cholesterol. By positional cloning methods, a gene (NPC1) with insertion, deletion, and missense mutations has been identified in NP-C patients. Transfection of NP-C fibroblasts with wild-type NPC1 cDNA resulted in correction of their excessive lysosomal storage of LDL cholesterol, thereby defining the critical role of NPC1 in regulation of intracellular cholesterol trafficking. The 1278-amino acid NPC1 protein has sequence similarity to the morphogen receptor PATCHED and the putative sterol-sensing regions of SREBP cleavage-activating protein (SCAP) and 3-hydroxy-3-methyl-glutaryl coenzyme A (HMG-CoA) reductase.

The Assessment of SpondyloArthritis International Society classification criteria for peripheral spondyloarthritis and for spondyloarthritis in general

OBJECTIVE

To evaluate new classification criteria for peripheral spondyloarthritis (SpA) in patients with SpA with peripheral manifestations only.

METHODS

In this Assessment of SpondyloArthritis international Society (ASAS) study, two prespecified sets of criteria were compared against the European Spondylarthropathy Study Group (ESSG) and Amor criteria in newly referred consecutive patients with undiagnosed peripheral arthritis, and/or enthesitis, and/or dactylitis that usually began before 45 years of age. The clinical diagnosis (SpA vs no SpA) made by the ASAS rheumatologist served as reference standard.

RESULTS

In all, 24 ASAS centres included 266 patients, with a final diagnosis of SpA being made in 66.2%. After adjustments a final set of criteria showed the best balance between sensitivity (77.8%) and specificity (82.9%): arthritis and/or enthesitis and/or dactylitis plus (A) one or more of the following parameters: psoriasis, inflammatory bowel disease, preceding infection, human leucocyte antigen B27, uveitis, sacroiliitis on imaging, or (B) two or more other parameters: arthritis, enthesitis, dactylitis, inflammatory back pain in the past, family history of SpA. The new criteria performed better than modified versions of the ESSG (sensitivity 62.5%, specificity 81.1%) and the Amor criteria (sensitivity 39.8%, specificity 97.8%), particularly regarding sensitivity. In the entire ASAS population of 975 patients the combined use of ASAS criteria for axial SpA and ASAS criteria for peripheral SpA also had a better balance (sensitivity 79.5%, specificity 83.3%) than the modified ESSG (sensitivity 79.1%, specificity 68.8%) and Amor criteria (sensitivity 67.5%, specificity 86.7%), respectively.

CONCLUSIONS

The new ASAS classification criteria for peripheral SpA performed well in patients presenting with peripheral arthritis, enthesitis and/or dactylitis.

Inhibition of cell migration, spreading, and focal adhesions by tumor suppressor PTEN

The tumor suppressor PTEN is a phosphatase with sequence similarity to the cytoskeletal protein tensin. Here the cellular roles of PTEN were investigated. Overexpression of PTEN inhibited cell migration, whereas antisense PTEN enhanced migration. Integrin-mediated cell spreading and the formation of focal adhesions were down-regulated by wild-type PTEN but not by PTEN with an inactive phosphatase domain. PTEN interacted with the focal adhesion kinase FAK and reduced its tyrosine phosphorylation. Overexpression of FAK partially antagonized the effects of PTEN. Thus, PTEN phosphatase may function as a tumor suppressor by negatively regulating cell interactions with the extracellular matrix.

Mutation of Pten/Mmac1 in mice causes neoplasia in multiple organ systems

Pten/Mmac1+/- heterozygous mice exhibited neoplasms in multiple organs including the endometrium, liver, prostate, gastrointestinal tract, thyroid, and thymus. Loss of the wild-type allele was detected in neoplasms of the thymus and liver. Surprisingly, tumors of the gastrointestinal epithelium developed in association with gut lymphoid tissue. Tumors of the endometrium, thyroid, prostate, and liver were not associated with lymphoid tissue and appeared to be highly mitotic. In addition, these mice have nonneoplastic hyperplasia of lymph nodes that was caused by an inherited defect in apoptosis detected in B cells and macrophages. Examination of peripheral lymphoid tissue including lymphoid aggregates associated with polyps revealed that the normal organization of B and T cells was disrupted in heterozygous animals. Taken together, these data suggest that PTEN is a regulator of apoptosis and proliferation that behaves as a "landscaper" tumor suppressor in the gut and a "gatekeeper" tumor suppressor in other organs.

Comparison of tocilizumab monotherapy versus methotrexate monotherapy in patients with moderate to severe rheumatoid arthritis: the AMBITION study

BACKGROUND

The anti-interleukin (IL) 6 receptor antibody tocilizumab inhibits signalling of IL6, a key cytokine in rheumatoid arthritis (RA) pathogenesis.

OBJECTIVE

To evaluate through the AMBITION study the efficacy and safety of tocilizumab monotherapy versus methotrexate in patients with active RA for whom previous treatment with methotrexate/biological agents had not failed.

METHODS

This 24-week, double-blind, double-dummy, parallel-group study, randomised 673 patients to either tocilizumab 8 mg/kg every 4 weeks, or methotrexate, starting at 7.5 mg/week and titrated to 20 mg/week within 8 weeks, or placebo for 8 weeks followed by tocilizumab 8 mg/kg. The primary end point was the proportion of patients achieving American College of Rheumatology (ACR) 20 response at week 24.

RESULTS

The intention-to-treat analysis demonstrated that tocilizumab was better than methotrexate treatment with a higher ACR20 response (69.9 vs 52.5%; p<0.001), and 28-joint Disease Activity Score (DAS28) <2.6 rate (33.6 vs 12.1%) at week 24. Mean high-sensitivity C-reactive protein was within the normal range from week 12 with tocilizumab, whereas levels remained elevated with methotrexate. The incidence of serious adverse events with tocilizumab was 3.8% versus 2.8% with methotrexate (p = 0.50), and of serious infections, 1.4% versus 0.7%, respectively. There was a higher incidence of reversible grade 3 neutropenia (3.1% vs 0.4%) and increased total cholesterol > or =240 mg/dl (13.2% vs 0.4%), and a lower incidence of alanine aminotransferase elevations >3x-<5x upper limit of normal (1.0% vs 2.5%), respectively.

CONCLUSION

Tocilizumab monotherapy is better than methotrexate monotherapy, with rapid improvement in RA signs and symptoms, and a favourable benefit-risk, in patients for whom treatment with methotrexate or biological agents has not previously failed.

Cytochrome c release and apoptosis induced by mitochondrial targeting of nuclear orphan receptor TR3

TR3, an immediate-early response gene and an orphan member of the steroid-thyroid hormone-retinoid receptor superfamily of transcription factors, regulates apoptosis through an unknown mechanism. In response to apoptotic stimuli, TR3 translocates from the nucleus to mitochondria to induce cytochrome c release and apoptosis. Mitochondrial targeting of TR3, but not its DNA binding and transactivation, is essential for its proapoptotic effect. Our results reveal a mechanism by which a nuclear transcription factor translocates to mitochondria to initiate apoptosis.

p73 is regulated by tyrosine kinase c-Abl in the apoptotic response to DNA damage

The protein p73 is a structural and functional homologue of the p53 tumour-suppressor protein but, unlike p53, it is not induced in response to DNA damage. The tyrosine kinase c-Abl is activated by certain DNA-damaging agents and contributes to the induction of programmed cell death (apoptosis) by p53-dependent and p53-independent mechanisms. Here we show that c-Abl binds to p73 in cells, interacting through its SH3 domain with the carboxy-terminal homo-oligomerization domain of p73. c-Abl phosphorylates p73 on a tyrosine residue at position 99 both in vitro and in cells that have been exposed to ionizing radiation. Our results show that c-Abl stimulates p73-mediated transactivation and apoptosis. This regulation of p73 by c-Abl in response to DNA damage is also demonstrated by a failure of ionizing-radiation-induced apoptosis after disruption of the c-Abl-p73 interaction. These findings show that p73 is regulated by a c-Abl-dependent mechanism and that p73 participates in the apoptotic response to DNA damage.

Characterization of the structure and function of the fourth member of p38 group mitogen-activated protein kinases, p38delta

We have cloned and characterized a new member of the p38 group of mitogen-activated protein kinases here termed p38delta. Sequence comparisons revealed that p38delta is approximately 60% identical to the other three p38 isoforms but only 40-45% to the other mitogen-activated protein kinase family members. It contains the TGY dual phosphorylation site present in all p38 group members and is activated by a group of extracellular stimuli including cytokines and environmental stresses that also activate the other three known p38 isoforms. However, unlike the other p38 isoforms, the kinase activity of p38delta is not blocked by the pyridinyl imidazole, 4-(4-fluorophenyl)-2-2(4-hydroxyphenyl)-5-(4-pyridyl)-imidazole (identicalto SB202190). p38delta can be activated by MKK3 and MKK6, known activators of the other isoforms. Nonetheless, in-gel kinase assays provide evidence for additional activators. The data presented herein show that p38delta has many properties that are similar to those of other p38 group members. Nonetheless important differences exist among the four members of the p38 group of enzymes, and thus each may have highly specific, individual contributions to biologic events involving activation of the p38 pathways.

Plasma levels of insulin-like growth factor-I and lung cancer risk: a case-control analysis

BACKGROUND

Insulin-like growth factors (IGFs), in particular IGF-I and IGF-II, strongly stimulate the proliferation of a variety of cancer cells, including those from lung cancer. To examine the possible causal role of IGFs in lung cancer development, we compared plasma levels of IGF-I, IGF-II, and an IGF-binding protein (IGFBP-3) in patients with newly diagnosed lung cancer and in control subjects.

METHODS

From an ongoing hospital-based, case-control study, we selected 204 consecutive patients with histologically confirmed, primary lung cancer and 218 control subjects who were matched to the case patients by age, sex, race, and smoking status. IGF-I, IGF-II, and IGFBP-3 plasma levels were measured by enzyme-linked immunosorbent assay and then divided into quartiles, based on their distribution in the control subjects. Associations between the IGF variables and lung cancer risk were estimated by use of odds ratios (ORs). Reported P values are two-sided.

RESULTS

IGF and IGFBP-3 levels were positively correlated (all r>.27; all P<.001). High plasma levels of IGF-I were associated with an increased risk of lung cancer (OR = 2.06; 95% confidence interval [CI] = 1.19-3.56; P = .01), and this association was dose dependent in both univariate and multivariate analyses. Plasma IGFBP-3 showed no association with lung cancer risk unless adjusted for IGF-I level; when both of these variables were analyzed together, high plasma levels of IGFBP-3 were associated with reduced risk of lung cancer (OR = 0.48; 95% CI = 0.25-0.92; P = .03). IGF-II was not associated with lung cancer risk.

CONCLUSIONS

Plasma levels of IGF-I are higher and plasma levels of IGFBP-3 are lower in patients with lung cancer than in control subjects. If these findings can be confirmed in prospective studies, measuring levels of IGF-I and IGFBP-3 in blood may prove useful in assessing lung cancer risk.

PTEN interactions with focal adhesion kinase and suppression of the extracellular matrix-dependent phosphatidylinositol 3-kinase/Akt cell survival pathway

The tumor suppressor PTEN is a phosphatase with sequence homology to tensin. PTEN dephosphorylates phosphatidylinositol 3,4, 5-trisphosphate (PIP3) and focal adhesion kinase (FAK), and it can inhibit cell growth, invasion, migration, and focal adhesions. We investigated molecular interactions of PTEN and FAK in glioblastoma and breast cancer cells lacking PTEN. The PTEN trapping mutant D92A bound wild-type FAK, requiring FAK autophosphorylation site Tyr397. In PTEN-mutated cancer cells, FAK phosphorylation was retained even in suspension after detachment from extracellular matrix, accompanied by enhanced PI 3-K association with FAK and sustained PI 3-K activity, PIP3 levels, and Akt phosphorylation; expression of exogenous PTEN suppressed all five properties. PTEN-mutated cells were resistant to apoptosis in suspension, but most of the cells entered apoptosis after expression of exogenous PTEN or wortmannin treatment. Moreover, overexpression of FAK in PTEN-transfected cells reversed the decreased FAK phosphorylation and PI 3-K activity, and it partially rescued PIP3 levels, Akt phosphorylation, and PTEN-induced apoptosis. Our results show that FAK Tyr397 is important in PTEN interactions with FAK, that PTEN regulates FAK phosphorylation and molecular associations after detachment from matrix, and that PTEN negatively regulates the extracellular matrix-dependent PI 3-K/Akt cell survival pathway in a process that can include FAK.

Improved section adhesion for immunocytochemistry using high molecular weight polymers of L-lysine as a slide coating

Poly-L-lysine (PPL) has been used to coat glass slides in the preparation of tissue sections for immunocytochemical staining. The adhesive properties of different molecular weight (m.w.) polymers of L-lysine have been tested on pre-fixed cryostat sections which were subjected to a 3 day washing treatment. It has been found that the higher the molecular weight of the polymer, the greater the adhesive force it provides. PLL (m.w. 350,000) at concentrations in the range of 0.05-0.1% was found to be the most effective polymer.

Tumor suppressor PTEN inhibits integrin- and growth factor-mediated mitogen-activated protein (MAP) kinase signaling pathways

The tumor suppressor PTEN dephosphorylates focal adhesion kinase (FAK) and inhibits integrin-mediated cell spreading and cell migration. We demonstrate here that expression of PTEN selectively inhibits activation of the extracellular signal-regulated kinase (ERK) mitogen-activated protein kinase (MAPK) pathway. PTEN expression in glioblastoma cells lacking the protein resulted in inhibition of integrin-mediated MAP kinase activation. Epidermal growth factor (EGF) and platelet-derived growth factor (PDGF)- induced MAPK activation were also blocked. To determine the specific point of inhibition in the Ras/Raf/ MEK/ERK pathway, we examined these components after stimulation by fibronectin or growth factors. Shc phosphorylation and Ras activity were inhibited by expression of PTEN, whereas EGF receptor autophosphorylation was unaffected. The ability of cells to spread at normal rates was partially rescued by coexpression of constitutively activated MEK1, a downstream component of the pathway. In addition, focal contact formation was enhanced as indicated by paxillin staining. The phosphatase domain of PTEN was essential for all of these functions, because PTEN with an inactive phosphatase domain did not suppress MAP kinase or Ras activity. In contrast to its effects on ERK, PTEN expression did not affect c-Jun NH2-terminal kinase (JNK) or PDGF-stimulated Akt. Our data suggest that a general function of PTEN is to down-regulate FAK and Shc phosphorylation, Ras activity, downstream MAP kinase activation, and associated focal contact formation and cell spreading.

Simultaneous targeting of multiple disease mediators by a dual-variable-domain immunoglobulin

For complex diseases in which multiple mediators contribute to overall disease pathogenesis by distinct or redundant mechanisms, simultaneous blockade of multiple targets may yield better therapeutic efficacy than inhibition of a single target. However, developing two separate monoclonal antibodies for clinical use as combination therapy is impractical, owing to regulatory hurdles and cost. Multi-specific, antibody-based molecules have been investigated; however, their therapeutic use has been hampered by poor pharmacokinetics, stability and manufacturing feasibility. Here, we describe a generally applicable model of a dual-specific, tetravalent immunoglobulin G (IgG)-like molecule--termed dual-variable-domain immunoglobulin (DVD-Ig)--that can be engineered from any two monoclonal antibodies while preserving activities of the parental antibodies. This molecule can be efficiently produced from mammalian cells and exhibits good physicochemical and pharmacokinetic properties. Preclinical studies of a DVD-Ig protein in an animal disease model demonstrate its potential for therapeutic application in human diseases.

Inhibition of hypoxia-inducible factor 1 activation by carbon monoxide and nitric oxide. Implications for oxygen sensing and signaling

It has been proposed that cells sense hypoxia by a heme protein, which transmits a signal that activates the heterodimeric transcription factor hypoxia-inducible factor 1 (HIF-1), thereby inducing a number of physiologically relevant genes such as erythropoietin (Epo). We have investigated the mechanism by which two heme-binding ligands, carbon monoxide and nitric oxide, affect oxygen sensing and signaling. Two concentrations of CO (10 and 80%) suppressed the activation of HIF-1 and induction of Epo mRNA by hypoxia in a dose-dependent manner. In contrast, CO had no effect on the induction of HIF-1 activity and Epo expression by either cobalt chloride or the iron chelator desferrioxamine. The affinity of CO for the putative sensor was much lower than that of oxygen (Haldane coefficient, approximately 0.5). Parallel experiments were done with 100 microM sodium nitroprusside, a nitric oxide donor. Both NO and CO inhibited HIF-1 DNA binding by abrogating hypoxia-induced accumulation of HIF-1alpha protein. Moreover, both NO and CO specifically targeted the internal oxygen-dependent degradation domain of HIF-1alpha, and also repressed the C-terminal transactivation domain of HIF-1alpha. Thus, NO and CO act proximally, presumably as heme ligands binding to the oxygen sensor, whereas desferrioxamine and perhaps cobalt appear to act at a site downstream.

Mutual dependence of MDM2 and MDMX in their functional inactivation of p53

MDMX, an MDM2-related protein, has emerged as yet another essential negative regulator of p53 tumor suppressor, since loss of MDMX expression results in p53-dependent embryonic lethality in mice. However, it remains unknown why neither homologue can compensate for the loss of the other. In addition, results of biochemical studies have suggested that MDMX inhibits MDM2-mediated p53 degradation, thus contradicting its role as defined in gene knockout experiments. Using cells deficient in either MDM2 or MDMX, we demonstrated that these two p53 inhibitors are in fact functionally dependent on each other. In the absence of MDMX, MDM2 is largely ineffective in down-regulating p53 because of its extremely short half-life. MDMX renders MDM2 protein sufficiently stable to function at its full potential for p53 degradation. On the other hand, MDMX, which is a cytoplasmic protein, depends on MDM2 to redistribute into the nucleus and be able to inactivate p53. We also showed that MDMX, when exceedingly overexpressed, inhibits MDM2-mediated p53 degradation by competing with MDM2 for p53 binding. Our findings therefore provide a molecular basis for the nonoverlapping activities of these two p53 inhibitors previously revealed in genetic studies.

Ciliary neurotropic factor, interleukin 11, leukemia inhibitory factor, and oncostatin M are growth factors for human myeloma cell lines using the interleukin 6 signal transducer gp130

Interleukin 6 (IL-6) is a major growth factor for tumor plasma cells involved in human multiple myeloma (MM). In particular, human myeloma cell lines (HMCL), whose growth is completely dependent on addition of exogenous IL-6, can be obtained reproducibly from every patient with terminal disease. Four cytokines, ciliary neurotropic factor (CNTF), IL-11, leukemia inhibitory factor (LIF), and oncostatin M (OM), use the same transducer chain (signal transducer gp130) as IL-6 and share numerous biological activities with this IL. We found that these four cytokines stimulated proliferation and supported the long-term growth of two out of four IL-6-dependent HMCL obtained in our laboratory. Half-maximal proliferation was obtained with cytokine concentrations ranging from 0.4 to 1.2 ng/ml for IL-11, LIF, and OM. CNTF worked at high concentrations only (90 ng/ml), but addition of soluble CNTF receptor increased sensitivity to CNTF 30-fold. The growth-promoting effect of these four cytokines was abrogated by anti-gp130 antibodies, contrary to results for anti-IL-6 receptor or anti-IL-6 antibodies. No detectable changes in the morphology and phenotype were found when myeloma cells were cultured with one of these four cytokines instead of IL-6. Concordant with their IL-6-dependent growth, the four HMCL expressed membrane IL-6R and gp130 detected by FACS analysis. LIF-binding chain gene (LIFR) was expressed only in the two HMCL responsive to LIF and OM.

Hsa-miR-9 methylation status is associated with cancer development and metastatic recurrence in patients with clear cell renal cell carcinoma

The long-term prognosis for clear cell renal cell carcinoma (ccRCC) is dramatically altered by the development of metastatic recurrence. However, there are very few indicators that can predict which patient will develop a recurrence. MicroRNAs regulate many cellular processes and have been shown to be associated with cancer development and recurrence. More recently it has been shown that microRNA genes can be epigenetically modified in cancer, resulting in aberrant silencing of microRNA genes with tumor suppressor functions. In this study, we show that two genes encoding for hsa-miR-9 are significantly hypermethylated in ccRCC tumors compared with adjacent normal tissues (P-value <0.001 for both miR-9-1 and miR-9-3) resulting in decreased expression, and that the methylation of these genes was more significant in DNA obtained from the primary tumor for patients who developed a recurrence (P-value: 0.012 and 0.009 for miR-9-1 and miR-9-3, respectively) than in tumors from nonrecurrent patients. Furthermore, methylation of miR-9-3 was significantly associated with an increased risk of recurrence (hazard ratio: 5.85, 95% confidence intervals: 1.30-26.35) and high methylation levels of either miR-9-1 or miR-9-3 resulted in a significant, nearly 30-month decrease in recurrence-free survival time (P-value: 0.034 and 0.007 for miR-9-1 and miR-9-3, respectively). Our results demonstrate that hsa-miR-9 is involved in the development of ccRCC while also having a role in the development of metastatic recurrence.

Neuropeptide tyrosine (NPY)--a major cardiac neuropeptide

A newly discovered bioactive peptide, neuropeptide tyrosine (NPY), has been found in the human cardiac nervous system. Dense concentrations of NPY-immunoreactive nerve fibres were found in association with nodal tissue (atrioventricular node 22.1 +/- 3.7 pmol/g). NPY nerve fibres were seen in close contact with cardiac muscle fibres and were also found around the coronary vessels (19.6 +/- 6.2 pmol/g). Analysis of the peptide by high-performance liquid chromatography demonstrated that it was present in a single molecular form, closely similar or identical to that of the isolated bioactive peptide. Cardiac function in man has long been known to be influenced by cholinergic and adrenergic nerves. There now appears to be a further component of the nervous system in the human heart, involving peptidergic nerves containing NPY.

An approach to rapid protein crystallization using nanodroplets

An approach that enables up to a two order of magnitude reduction in the amount of protein required and a tenfold reduction in the amount of time required for vapor-diffusion protein crystallization is reported. A prototype high-throughput automated system was used for the production of diffraction-quality crystals for a variety of proteins from a screen of 480 conditions using drop volumes as small as 20 nL. This approach results in a significant reduction in the time and cost of protein structure determination, and allows for larger and more efficient screens of crystallization parameter space. The ability to produce diffraction-quality crystals rapidly with minimal quantities of protein enables high-throughput efforts in structural genomics and structure-based drug discovery.

Tumor formation and inactivation of RIZ1, an Rb-binding member of a nuclear protein-methyltransferase superfamily

The retinoblastoma protein-interacting zinc finger gene RIZ (PRDM2) is a member, by sequence homology, of a nuclear protein-methyltransferase (MTase) superfamily involved in chromatin-mediated gene expression. The gene produces two protein products, RIZ1 that contains a conserved MTase domain and RIZ2 that lacks the domain. RIZ1 gene expression is frequently silenced in human cancers, and the gene is also a common target of frameshift mutation in microsatellite-unstable cancers. We now report studies of mice with a targeted mutation in the RIZ1 locus. The mutation inactivates RIZ1 but not RIZ2. These RIZ1 mutant mice were viable and fertile but showed a high incidence of diffuse large B-cell lymphomas (DLBL) and a broad spectrum of unusual tumors. RIZ1 deficiency also accelerated tumorigenesis in p53 heterozygous mutant mice. Finally, several missense mutations of RIZ1 were found in human tumor tissues and cell lines; one of these was particularly common in human DLBL tumors. These missense mutations, as well as the previously described frameshift mutation, all mapped to the MTase functional domains. All abolished the capacity of RIZ1 to enhance estrogen receptor activation of transcription. These data suggest a direct link between tumor formation and the MTase domain of RIZ1 and describe for the first time a tumor susceptibility gene among methyltransferases.

Cloning and functional analysis of cDNAs with open reading frames for 300 previously undefined genes expressed in CD34+ hematopoietic stem/progenitor cells

Three hundred cDNAs containing putatively entire open reading frames (ORFs) for previously undefined genes were obtained from CD34+ hematopoietic stem/progenitor cells (HSPCs), based on EST cataloging, clone sequencing, in silico cloning, and rapid amplification of cDNA ends (RACE). The cDNA sizes ranged from 360 to 3496 bp and their ORFs coded for peptides of 58-752 amino acids. Public database search indicated that 225 cDNAs exhibited sequence similarities to genes identified across a variety of species. Homology analysis led to the recognition of 50 basic structural motifs/domains among these cDNAs. Genomic exon-intron organization could be established in 243 genes by integration of cDNA data with genome sequence information. Interestingly, a new gene named as HSPC070 on 3p was found to share a sequence of 105bp in 3' UTR with RAF gene in reversed transcription orientation. Chromosomal localizations were obtained using electronic mapping for 192 genes and with radiation hybrid (RH) for 38 genes. Macroarray technique was applied to screen the gene expression patterns in five hematopoietic cell lines (NB4, HL60, U937, K562, and Jurkat) and a number of genes with differential expression were found. The resource work has provided a wide range of information useful not only for expression genomics and annotation of genomic DNA sequence, but also for further research on the function of genes involved in hematopoietic development and differentiation.

Laminin-10/11 and Fibronectin Differentially Regulate Integrin- dependent Rho and Rac Activation via p130Cas-CrkII-DOCK180 Pathway

The alpha(5) chain-containing laminin isoforms, laminins-10 and -11 (laminin-10/11), are the major components of the basement membrane, having potent cell-adhesive activity. We examined the cell-adhesive and integrin-mediated signaling activities of laminin-10/11 in comparison to fibronectin, the best characterized extracellular adhesive ligand. We found that laminin-10/11 are more active than fibronectin in promoting cell migration and preferentially activate Rac, not Rho, via the p130(Cas)-CrkII-DOCK180 pathway. Cells adhering to fibronectin develop stress fibers and focal contacts, whereas cells adhering to laminin-10/11 do not, consistent with the high cell migration-promoting activity of laminin-10/11. Pull-down assays of GTP-loaded Rac and Rho demonstrated the preferential activation of Rac on laminin-10/11, in contrast to the activation of Rho on fibronectin. Activation of Rac by laminin-10/11 was associated with the phosphorylation of p130(Cas) and an increased formation of a p130(Cas)-CrkII-DOCK180 complex. Cell migration on laminin-10/11 was suppressed by the expression of either a dominant-negative Rac or CrkII mutants defective in p130(Cas) or DOCK180 binding. This is the first report demonstrating a distinct activation of Rho family GTPases resulting from adhesion to different extracellular ligands.