bri3, a novel gene, participates in tumor necrosis factor-alpha-induced cell death

Breastmilk polyamines modify gut gene expression in children at three months of age

BACKGROUND & AIMS

Breastmilk is one of the main sources of exogenous polyamines for newborns and contains higher polyamine content than infant formulas. Polyamines are involved in gut maturation and immune system regulation in animals, although the underlying mechanisms are not fully understood. We quantified polyamines in human mature breastmilk and evaluate their effects on intestinal gene expression in babies at three months of age.

METHODS

Polyamines were quantified in mature milk of 195 women from the prospective Mediterranean NELA birth cohort (Murcia, Spain) at 3 months postpartum. Maternal dietary intake was assessed by food frequency questionnaires. Intestinal gene expression was analysed in babies receiving breastmilk, with high (>p50, n = 25) or low (

RESULTS

Spermidine and spermine were the most prevalent polyamines in breastmilk at 3 months postpartum, while levels of putrescine were lower. Maternal dietary intake of polyamines was not associated with polyamine concentration in breastmilk and there were no differences in the polyamine content between allergic and non-allergic mothers. Microarray analyses of exfoliated gut cells revealed that cell localization and immune system were the most significant biological processes affected by high vs low polyamines in breastmilk. There were 15 differentially expressed genes, 3 up-regulated and 12 down-regulated, in high compared to low polyamine groups. Among the up-regulated genes were tumour necrosis factor alpha-induced protein 6 (TNFAIP6) and interleukin 8; while other immune system-related genes, such as integral membrane protein 2C, lymphocyte antigen 6 complex, transmembrane protein 179B were down-regulated.

CONCLUSIONS

Mature breastmilk presents spermidine and spermine as the most prevalent polyamines. Babies receiving milk with higher polyamine levels showed differences in the expression of genes associated with cell localization and immune system processes.

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Key Words

• Breastmilk
• Exfoliome
• Gene expression
• Intestine
• Polyamines
• Transcriptome

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MESH Headings

• Humans
• Milk, Human/chemistry
• Infant
• Female
• Polyamines/metabolism
• Prospective Studies
• Male
• Adult
• Gene Expression/drug effects
• Spermidine
• Spain
• Breast Feeding
• Putrescine

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Affiliation(s)

María Sánchez-Campillo Biomedical Research Institute of Murcia (IMIB-Arrixaca), Murcia, Spain; Department of Physiology, University of Murcia, Murcia, Spain
Antonio Gázquez Biomedical Research Institute of Murcia (IMIB-Arrixaca), Murcia, Spain; Department of Physiology, University of Murcia, Murcia, Spain; Maternal and Child Health and Development Research Network (RICORS-SAMID), Institute of Health Carlos III, Madrid, Spain
María T Pastor-Fajardo Biomedical Research Institute of Murcia (IMIB-Arrixaca), Murcia, Spain; Department of Pediatrics, Hospital General Universitario de Elche, Alicante, Spain
María J López-Andreo Biology Molecular Section (ACTI), University of Murcia, Murcia, Spain
Adrián Pérez-Andrés Department of Physiology, University of Murcia, Murcia, Spain
Carmen Martínez-Graciá Biomedical Research Institute of Murcia (IMIB-Arrixaca), Murcia, Spain; Food Science and Technology Department, Faculty of Veterinary, University of Murcia, Murcia, Spain
Jesús Vioque Health and Biomedical Research Institute of Alicante, University Miguel Hernandez (ISABIAL-UMH), Alicante, Spain; CIBER Epidemiology and Public Health (CIBERESP), Madrid, Spain
Virginia Pérez-Fernández Biomedical Research Institute of Murcia (IMIB-Arrixaca), Murcia, Spain; Department of Sociosanitary Sciences, Faculty of Medicine, University of Murcia, Murcia, Spain
Luís García-Marcos Biomedical Research Institute of Murcia (IMIB-Arrixaca), Murcia, Spain; Network of Asthma and Adverse and Allergic Reactions (ARADyAL), Madrid, Spain; Pediatric Allergy and Pulmonology Units, Virgen de la Arrixaca University Children's Hospital, University of Murcia, Murcia, Spain
Elvira Larqué Biomedical Research Institute of Murcia (IMIB-Arrixaca), Murcia, Spain; Department of Physiology, University of Murcia, Murcia, Spain; Maternal and Child Health and Development Research Network (RICORS-SAMID), Institute of Health Carlos III, Madrid, Spain.

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Long noncoding RNA profiling in hepatopancreas of Pacific white shrimp and its role in response to white spot syndrome virus infection

Long noncoding RNA (lncRNA) is a potential regulator of biological processes, including immunity, reproduction, and development. Although several transcriptome studies have focused on responses of viral infections in several organisms, the role of lncRNAs in viral responses in shrimp is still unclear. Therefore, this work aimed to identify putative lncRNAs and study their role in white spot syndrome virus (WSSV) infection in white shrimp. The hepatopancreas transcriptome from WSSV infected shrimp was analyzed in silico to identify putative lncRNAs. Among 221,347 unigenes of the de novo assembled transcriptome, 44,539 putative lncRNAs were identified, 32 of which were differentially expressed between WSSV-infected and control shrimp. Five candidate lncRNAs were validated for their expressions in shrimp tissues and in response to WSSV infection. Lnc164 was chosen for further investigation of its role in WSSV infection. Knockdown of lnc164 prolonged survival of shrimp when challenged with WSSV, suggesting a role in shrimp immunity. In addition, lnc164 was not directly involved in the control of total hemocytes and viral loads in hemolymph of WSSV-infected shrimp. A set of lnc164-regulated genes was obtained by RNA sequencing among which 251 transcripts were differentially expressed between lnc164 knockdown and control shrimp. Six immune-related genes were validated for their expression profiles. Our work sheds light on lncRNA profiles in L. vannamei in response to WSSV infection and paves the way to a functional study of lnc164 in host antiviral response.

Autophagy modulators influence the content of important signalling molecules in PS-positive extracellular vesicles

Extracellular vesicles (EVs) are important mediators of intercellular communication in the tumour microenvironment. Many studies suggest that cancer cells release higher amounts of EVs exposing phosphatidylserine (PS) at the surface. There are lots of interconnections between EVs biogenesis and autophagy machinery. Modulation of autophagy can probably affect not only the quantity of EVs but also their content, which can deeply influence the resulting pro-tumourigenic or anticancer effect of autophagy modulators. In this study, we found that autophagy modulators autophinib, CPD18, EACC, bafilomycin A1 (BAFA1), 3-hydroxychloroquine (HCQ), rapamycin, NVP-BEZ235, Torin1, and starvation significantly alter the composition of the protein content of phosphatidylserine-positive EVs (PS-EVs) produced by cancer cells. The greatest impact had HCQ, BAFA1, CPD18, and starvation. The most abundant proteins in PS-EVs were proteins typical for extracellular exosomes, cytosol, cytoplasm, and cell surface involved in cell adhesion and angiogenesis. PS-EVs protein content involved mitochondrial proteins and signalling molecules such as SQSTM1 and TGFβ1 pro-protein. Interestingly, PS-EVs contained no commonly determined cytokines, such as IL-6, IL-8, GRO-α, MCP-1, RANTES, and GM-CSF, which indicates that secretion of these cytokines is not predominantly mediated through PS-EVs. Nevertheless, the altered protein content of PS-EVs can still participate in the modulation of the fibroblast metabolism and phenotype as p21 was accumulated in fibroblasts influenced by EVs derived from CPD18-treated FaDu cells. The altered protein content of PS-EVs (data are available via ProteomeXchange with identifier PXD037164) also provides information about the cellular compartments and processes that are affected by the applied autophagy modulators. Video Abstract.

Immune activation of characteristic gut mycobiota Kazachstania pintolopesii on IL-23/IL-17R signaling in ankylosing spondylitis

It is very important to understand the communication and interaction mechanisms between the host and its resident microorganisms on host physiology and for precise diagnosis and treatment. Although intestinal fungi and bacteria dysbiosis is increasingly linked to ankylosing spondylitis (AS), their mechanisms of action have been rarely illustrated. In this paper, fecal samples from 10 AS monkeys and 10 healthy controls were collected to systematically characterize the gut mycobiota and microbiota in AS monkeys by 16S rRNA and ITS2 DNA sequencing. Our results showed the gut fungi of Kazachstania pintolopesii, Saccharomycetaceae, Kazachstania, and Saccharomyceteles. Saccharomycetes were specially enriched in AS, and the microbiota of AS monkeys was characterized by an increased abundance of Clostridia, Clostridiales, Ruminococcaceae, and Prevotella 2, using Line Discriminant Analysis Effect Size. Compared to healthy controls, decreased ITS2/16S biodiversity ratios and altered bacterial-fungal interkingdom networks were observed in AS monkeys. Oral administration of K. pintolopesii activates IL-17RA pathway and induce inflammatory reaction in the colonic tissue of C57BL/6 mice, as well as multiple AS phenotypes, including fungal and bacterial dysbiosis, immune responses of NK cells, platelets, T cells, leukocytes, B-cell activation, rheumatoid arthritis, and inflammatory bowel disease. We also found the secreted products of K. pintolopesii could activate the IL-17RA pathway, which induces PANoptosis in macrophage RAW264.7 cells. Much worse, the PANoptosis products could promote the proliferation and morphological changes of K. pintolopesii, which resulted in much more K. pintolopesii and a severe inflammatory reaction. Interestingly, the inflammatory factor TNF-α can promote the morphological transformation of Candida albicans and K. pintolopesii, which is worthy of further study. The characteristic fungi in all these findings implied that fungal and bacterial dysbiosis have a close link to AS and that their communication and interaction indeed play an important role in autoimmune responses, and K. pintolopesii could be a potential marker microorganism in AS, although its specific mechanism is not fully elucidated.

Human adipose tissue-derived stem cell paracrine networks vary according metabolic risk and after TNFα-induced death: An analysis at the single-cell level

OBJECTIVE

Adipose tissue-derived stem cells (ASCs) might play an important role in adipose microenvironment remodelling during tissue expansion through their response to hypoxia. We examined the cytokine profiles of hypoxic visceral ASCs (hypox-visASCs) from subjects with different metabolic risk, the interactions between cytokines as well as the impact of TNFα-induced death in the behavior of surviving hypoxic subcutaneous ASCs (hypox-subASCs) both at bulk population and single-cell level.

MATERIALS/METHODS

Visceral adipose tissue was processed to isolate the ASCs from 33 subjects grouped into normal weight, obese with and without metabolic syndrome. Multiplex assay was used to simultaneously measure multiple inflammatory, anti-inflammatory and angiogenic cytokines in hypox-visASCs from these patients and to elucidate cytokine profiles of hypox-subASCs upon stimulation with IL1β or TNFα and after TNFα-induced death. qPCR and single-cell RNA-sequencing were also performed to elucidate transcriptional impact in surviving hypox-subASCs after TNFα-induced apoptosis.

RESULTS

Hypox-visASCs from subjects without metabolic syndrome showed greater secretion levels of inflammatory, anti-inflammatory and angiogenic cytokines compared with those from patients with metabolic syndrome. While IL-1β stimulation was sufficient to increase the secretion levels of these cytokines in hypox-subASCs, TNFα-induced apoptosis also increased their levels and impacted on the expression levels of extracellular matrix proteins, acetyl-CoA producing enzymes and redox-balance proteins in surviving hypox-subASCs. TNFα-induced apoptosis under different glucose concentrations caused selective impoverishment of cell clusters and differentially influenced gene expression profiles of surviving hypox-subASCs.

CONCLUSIONS

Immunoregulatory and angiogenic functions of hypox-visASCs from patients with metabolic syndrome could be insufficient to promote healthy adipose tissue expansion. TNFα-induced apoptosis may impact on functionality of hypox-subASC populations, whose differential metabolic sensitivity to death could serve to manipulate individual populations selectively in order to elucidate their role in shaping adipose heterogeneity and treating metabolic disorders.

Identification of IFITM3 and MGAT1 as novel interaction partners of BRI3 by yeast two-hybrid screening

BRI3 (brain protein I3) is one of the Wnt/β-catenin pathway target genes as indicated by the results of serial analysis of gene expression (SAGE) and microarray analyses performed in our laboratory. The Wnt/β-catenin signaling pathway is an evolutionarily conserved pathway, which has important functions in early vertebrate development, axis formation, cellular proliferation, and morphogenesis. Previous studies showed that BRI3 expression is upregulated at both mRNA and protein levels upon β-catenin activation by various approaches, such as lithium treatment and overexpression of Wnt ligands in Huh7 (hepatocellular carcinoma) cell lines. Moreover, with regard to the previous literature, BRI3 was found to have a very important role in the TNFα-mediated cell death pathway. In this study, we screened a human liver cDNA library by yeast two-hybrid assay using BRI3 protein as bait, with the aim of finding novel interaction partners of BRI3. Library screening by yeast mating resulted in the identification of three candidate positive clones. Among these, IFITM3 and MGAT1 proteins were confirmed as interaction partners by using cotransformation in yeast cells and coimmunoprecipitation from mammalian cell lines. Considering the poor functional characterization of BRI3 to date, identification of novel BRI3-interacting proteins is an essential first step in determining the action mechanism of BRI3 with respect to the Wnt/β-catenin pathway.

Identification of key genes relevant to the prognosis of ER-positive and ER-negative breast cancer based on a prognostic prediction system

Few prognostic indicators with differential expression have been reported among the differing ER statuses. We aimed to screen important breast cancer prognostic genes related to ER status and to construct an efficient prognostic prediction system. mRNA expression profiles were downloaded from TCGA and GSE70947 dataset. Two hundred seventy-one overlapping differentially expressed genes (DEGs) between the ER- and ER+ breast cancer samples were identified. Among the 271 DEGs, 109 prognostically relevant mRNAs were screened. mRNAs such as RASEF, ITM2C, CPEB2, ESR1, ANXA9, and VASN correlated strongly with breast cancer prognosis. Three modules, which contained 28, 9 and 8 enriched DEGs, were obtained from the network, and the DEGs in these modules were enriched in response to hormone stimulus, epithelial cell development, and host cell entry. Using bayes discriminant analysis, 48 signature genes were screened. We constructed a prognostic prediction system using the 48 signature genes and validated this system as relatively accurate and reliable. The DEGs might be closely associated with the prognosis in patients with breast cancer. We validated the effectiveness of our prognostic prediction system by GEO database. Therefore, this system might be a useful tool for preliminary screening and validation of potential prognosis indicators for ER+ breast cancer derived from mechanistic research.

Mining the Plasma Cell Transcriptome for Novel Cell Surface Proteins

Antibody Secreting Cells (ASCs) are a fundamental component of humoral immunity, however, deregulated or excessive antibody production contributes to the pathology of autoimmune diseases, while transformation of ASCs results in the malignancy Multiple Myeloma (MM). Despite substantial recent improvements in treating these conditions, there is as yet no widely used ASC-specific therapeutic approach, highlighting a critical need to identify novel methods of targeting normal and malignant ASCs. Surface molecules specifically expressed by the target cell population represent ideal candidates for a monoclonal antibody-based therapy. By interrogating the ASC gene signature that we previously defined we identified three surface proteins, Plpp5, Clptm1l and Itm2c, which represent potential targets for novel MM treatments. Plpp5, Clptm1l and Itm2c are highly and selectively expressed by mouse and human ASCs as well as MM cells. To investigate the function of these proteins within the humoral immune system we have generated three novel mouse strains, each carrying a loss-of-function mutation in either Plpp5, Clptm1l or Itm2c. Through analysis of these novel strains, we have shown that Plpp5, Clptm1l and Itm2c are dispensable for the development, maturation and differentiation of B-lymphocytes, and for the production of antibodies by ASCs. As adult mice lacking either protein showed no apparent disease phenotypes, it is likely that targeting these molecules on ASCs will have minimal on-target adverse effects.

PD-1 Blockade and CD27 Stimulation Activate Distinct Transcriptional Programs That Synergize for CD8+ T-Cell-Driven Antitumor Immunity

Purpose: PD-1 checkpoint blockade has revolutionized the field of cancer immunotherapy, yet the frequency of responding patients is limited by inadequate T-cell priming secondary to a paucity of activatory dendritic cells (DC). DC signals can be bypassed by CD27 agonists, and we therefore investigated if the effectiveness of anti-PD-1/L1 could be improved by combining with agonist anti-CD27 monoclonal antibodies (mAb).Experimental Design: The efficacy of PD-1/L1 blockade or agonist anti-CD27 mAb was compared with a dual-therapy approach in multiple tumor models. Global transcriptional profiling and flow cytometry analysis were used to delineate mechanisms underpinning the observed synergy.Results: PD-1/PD-L1 blockade and agonist anti-CD27 mAb synergize for increased CD8+ T-cell expansion and effector function, exemplified by enhanced IFNγ, TNFα, granzyme B, and T-bet. Transcriptome analysis of CD8+ T cells revealed that combination therapy triggered a convergent program largely driven by IL2 and Myc. However, division of labor was also apparent such that anti-PD-1/L1 activates a cytotoxicity-gene expression program whereas anti-CD27 preferentially augments proliferation. In tumor models, either dependent on endogenous CD8+ T cells or adoptive transfer of transgenic T cells, anti-CD27 mAb synergized with PD-1/L1 blockade for antitumor immunity. Finally, we show that a clinically relevant anti-human CD27 mAb, varlilumab, similarly synergizes with PD-L1 blockade for protection against lymphoma in human-CD27 transgenic mice.Conclusions: Our findings suggest that suboptimal T-cell invigoration in cancer patients undergoing treatment with PD-1 checkpoint blockers will be improved by dual PD-1 blockade and CD27 agonism and provide mechanistic insight into how these approaches cooperate for CD8+ T-cell activation. Clin Cancer Res; 24(10); 2383-94. ©2018 AACR.

Mitochondrial DNA plasticity is an essential inducer of tumorigenesis

Although mitochondrial DNA has been implicated in diseases such as cancer, its role remains to be defined. Using three models of tumorigenesis, namely glioblastoma multiforme, multiple myeloma and osteosarcoma, we show that mitochondrial DNA plays defining roles at early and late tumour progression. Specifically, tumour cells partially or completely depleted of mitochondrial DNA either restored their mitochondrial DNA content or actively recruited mitochondrial DNA, which affected the rate of tumorigenesis. Nevertheless, non-depleted tumour cells modulated mitochondrial DNA copy number at early and late progression in a mitochondrial DNA genotype-specific manner. In glioblastoma multiforme and osteosarcoma, this was coupled with loss and gain of mitochondrial DNA variants. Changes in mitochondrial DNA genotype affected tumour morphology and gene expression patterns at early and late progression. Importantly, this identified a subset of genes that are essential to early progression. Consequently, mitochondrial DNA and commonly expressed early tumour-specific genes provide novel targets against tumorigenesis.

BRI2 and BRI3 are functionally distinct phosphoproteins

Three BRI protein family members have been identified. Among these are BRI3 and BRI2, the latter is associated with Familial Danish and Familial British dementias. 'In silico' sequence analysis identified putative PP1 binding sites in BRI2 and BRI3. This is singularly important, given that protein phosphorylation is a major mechanism regulating intracellular processes. Protein phosphatase 1 (PP1) interacting proteins (PIPs) are fundamental in determining substrate specificity and subcellular localization of this phosphatase. More than 200 PIPs have thus far been reported. Both BRI2 and BRI3 are type II transmembrane glycoproteins relevant in neuronal systems. Using Myc-BRI2 and Myc-BRI3, wild type and PP1 binding mutant constructs, it was possible to show, for the first time, that in fact BRI2 and BRI3 bind PP1. The complexes BRI2:PP1 and BRI3:PP1 were validated in vitro and in vivo. The subcellular distribution of BRI2 and BRI3 is similar; both localize to the perinuclear area and Golgi apparatus in non-neuronal cells. However, in SH-SY5Y cells, BRI2 and BRI3 could also be detected in elongated cellular projections ('processes') and in rat cortical neurons both are broadly distributed throughout the cell body, neuritis and the nucleus. Consistently, co-localization of BRI2 and BRI3 with PP1 was evident. The functional significance of these complexes is apparent given that both BRI proteins are substrates of PP1, thus simultaneously this is the first report of BRI2 and BRI3 as phosphoproteins. Moreover, we show that when BRI2 is phosphorylated a significant increase in neuronal outgrowth and differentiation is evident. Interestingly, the Alzheimer's amyloid precursor protein (APP), forms a trimeric complex composed of PP1 and Fe65, with PP1 having the capacity to dephosphorylate APP at Thr668 residue. The emerging consensus appears to be that PP1 containing complexes are crucial in regulating signaling events underlying neuropathological conditions.

Probing the virus host interaction in high containment: an approach using pooled short hairpin RNA

The study of viruses in high containment offers unique challenges for technology-intense approaches. These approaches include high-throughput screening for small-molecule antivirals and genetic perturbation-based screens for host factors required for viral replication. Here, we describe the use of whole-genome scale pooled short hairpin RNA (shRNA) libraries to screen for host factors necessary for viral infection at BSL2, and the transition of this technique into the BSL4 environment. Pooled screening provides a unique way to circumvent many of the technological challenges associated with other high-throughput screening approaches in high containment. Our pooled screening approach identified host factors involved in the replication of orthopoxviruses (Vaccinia and Monkeypox) and filoviruses (Ebola and Marburg) under conditions that enable straightforward screen-to-follow-up approaches.

Nifedipine promotes the proliferation and migration of breast cancer cells

Nifedipine is widely used as a calcium channel blocker (CCB) to treat angina and hypertension,but it is controversial with respect the risk of stimulation of cancers. In this study, we demonstrated that nifedipine promoted the proliferation and migration of breast cancer cells both invivo and invitro. However, verapamil, another calcium channel blocker, didn't exert the similar effects. Nifedipine and high concentration KCl failed to alter the [Ca2+]i in MDA-MB-231 cells, suggesting that such nifedipine effect was not related with calcium channel. Moreover, nifedipine decreased miRNA-524-5p, resulting in the up-regulation of brain protein I3 (BRI3). Erk pathway was consequently activated and led to the proliferation and migration of breast cancer cells. Silencing BRI3 reversed the promoting effect of nifedipine on the breast cancer. In a summary, nifedipine stimulated the proliferation and migration of breast cancer cells via the axis of miRNA-524-5p-BRI3-Erk pathway independently of its calcium channel-blocking activity. Our findings highlight that nifedipine but not verapamil is conducive for breast cancer growth and metastasis, urging that the caution should be taken in clinic to prescribe nifedipine to women who suffering both hypertension and breast cancer, and hypertension with a tendency in breast cancers.

Physiological change under OsHV-1 contamination in Pacific oyster Crassostrea gigas through massive mortality events on fields

BACKGROUND

Massive mortalities have been observed in France since 2008 on spat and juvenile Pacific oysters, Crassostrea gigas. A herpes virus called OsHV-1, easily detectable by PCR, has been implicated in the mortalities as demonstrated by the results of numerous field studies linking mortality with OsHV-1 prevalence. Moreover, experimental infections using viral particles have documented the pathogenicity of OsHV-1 but the physiological responses of host to pathogen are not well known.

RESULTS

The aim of this study was to understand mechanisms brought into play against the virus during infection in the field. A microarray assay has been developed for a major part of the oyster genome and used for studying the host transcriptome across mortality on field. Spat with and without detectable OsHV-1 infection presenting or not mortality respectively were compared by microarray during mortality episodes. In this study, a number of genes are regulated in the response to pathogen infection on field and seems to argue to an implication of the virus in the observed mortality. The result allowed establishment of a hypothetic scheme of the host cell's infection by, and response to, the pathogen.

CONCLUSIONS

This response shows a "sensu stricto" innate immunity through genic regulation of the virus OsHV-1 life cycle, but also others biological processes resulting to complex interactions between host and pathogens in general.

Analysis of the prostate cancer cell line LNCaP transcriptome using a sequencing-by-synthesis approach

Background

High throughput sequencing-by-synthesis is an emerging technology that allows the rapid production of millions of bases of data. Although the sequence reads are short, they can readily be used for re-sequencing. By re-sequencing the mRNA products of a cell, one may rapidly discover polymorphisms and splice variants particular to that cell.

Results

We present the utility of massively parallel sequencing by synthesis for profiling the transcriptome of a human prostate cancer cell-line, LNCaP, that has been treated with the synthetic androgen, R1881. Through the generation of approximately 20 megabases (MB) of EST data, we detect transcription from over 10,000 gene loci, 25 previously undescribed alternative splicing events involving known exons, and over 1,500 high quality single nucleotide discrepancies with the reference human sequence. Further, we map nearly 10,000 ESTs to positions on the genome where no transcription is currently predicted to occur. We also characterize various obstacles with using sequencing by synthesis for transcriptome analysis and propose solutions to these problems.

Conclusion

The use of high-throughput sequencing-by-synthesis methods for transcript profiling allows the specific and sensitive detection of many of a cell's transcripts, and also allows the discovery of high quality base discrepancies, and alternative splice variants. Thus, this technology may provide an effective means of understanding various disease states, discovering novel targets for disease treatment, and discovery of novel transcripts.

Beta-amyloid protein converting enzyme 1 and brain-specific type II membrane protein BRI3: binding partners processed by furin

Using a yeast two-hybrid system, we screened a human brain cDNA library for possible interacting proteins with the C-terminal cytosolic tail of the beta-secretase beta-amyloid protein converting enzyme (BACE)1. This identified seven potential candidates, including the brain-specific type II membrane protein BRI3. Co-localization and co-immunoprecipitation experiments confirmed that BACE1 and BRI3 co-localize and interact with each other via the cytosolic tail of BACE1. Furthermore, pulse and pulse-chase analyses revealed that the pro-protein convertases furin, and to a lesser extent PC7 and PC5A, process BRI3 into a C-terminal secreted approximately 4-kDa product. Thus, furin efficiently processes both pro-BACE1 and its novel interacting protein pro-BRI3.

Crystallization and preliminary X-ray analysis of the GST-fused human Bri3 N-terminal domain

Bri3 is a recently identified proline-rich transmembrane polypeptide up-regulated during TNF-mediated inflammation and immunity. The polyproline-rich N-terminal (residues 1-60) domain of Bri3 was affinity-purified to homogeneity as a glutathione-S-transferase (GST) fusion protein. Crystals were obtained in approximately 3 d by the equilibrium vapour-diffusion method from a solution containing 1.5-2.2 M ammonium sulfate and 0.1 M bis-tris pH 6.0. The crystals belong to space group P4(3)2(1)2, with unit-cell parameters a = b = 91.66, c = 57.53 A. An X-ray data set was collected to 1.6 A resolution using synchrotron radiation, with an Rsym of 0.058 and a completeness of 95.3%. There is one molecule of the fusion protein in the asymmetric unit, which corresponds to approximately 35% solvent content.