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Env Gene (env + gene)
Selected AbstractsMouse mammary tumor-like env gene as a molecular marker for breast cancer?INTERNATIONAL JOURNAL OF CANCER, Issue 3 2002Rachel Zangen First page of article [source] An optimized nested polymerase chain reaction (PCR) approach allows detection and characterization of human immunodeficiency virus type 1 (HIV-1) env and gag genes from clinical samplesJOURNAL OF CLINICAL LABORATORY ANALYSIS, Issue 2 2008Dayse Locateli Abstract The needs for development and/or improvement of molecular approaches for microorganism detection and characterization such as polymerase chain reaction (PCR) are of high interest due their sensitivity and specificity when compared to traditional microbiological techniques. Considering the worldwide importance of human immunodeficiency virus type 1 (HIV-1) infection, it is essential that such approaches consider the genetic variability of the virus, the heterogeneous nature of the clinical samples, the existence of contaminants and inhibitors, and the consequent needs for standardization in order to guarantee the reproducibility of the methods. In this work we describe a nested PCR assay targeting HIV-1 virus gag and env genes, allowing specific and sensitive diagnosis and further direct characterization of clinical samples. The method described herein was tested on clinical samples and allowed the detection of HIV-1 presence in all samples tested for the gag gene and 90.9% for the env gene, revealing sensitivities of 1,fg and 100,fg, respectively. Also, no cross-reactions were observed with DNA from infected and noninfected patients and the method allowed detection of the env and gag genes on an excess of 108 and 104 of human deoxyribonucleic acid (DNA), respectively. Furthermore, it was possible to direct sequence all amplified products, which allowed the sub typing of the virus in clinical samples. J. Clin. Lab. Anal. 22:106,113, 2008. © 2008 Wiley-Liss, Inc. [source] Molecular characterization of the env gene of two CCR5/CXCR4-independent human immunodeficiency 2 primary isolates,JOURNAL OF MEDICAL VIROLOGY, Issue 11 2009Quirina Santos-Costa Abstract Human immunodeficiency virus 2 (HIV-2) infection is characterized by a slower disease progression and lower transmission rates. The molecular features that could be assigned as directly involved in this in vivo phenotype remain essentially unknown, and the importance of HIV-2 as a model to understand pathogenicity of HIV infection has been frequently underestimated. The early events of the HIV replication cycle involve the interaction between viral envelope glycoproteins and cellular receptors: the CD4 molecule and a chemokine receptor, usually CCR5 or CXCR4. Despite the importance of these two chemokine receptors in human immunodeficiency virus 1 (HIV-1) entry into cells, we have previously shown that in some HIV-2 asymptomatic individuals, a viral population exists that is unable to use both CCR5 and CXCR4. The goal of the present study was to investigate whether possible regions in the env gene of these viruses might account for this phenotype. From the molecular characterization of these env genes we could not detect any correlation between V3 loop sequence and viral phenotype. In contrast, it reveals the existence of remarkable differences in the V1/V2 and C5 regions of the surface glycoprotein, including the loss of a putative glycosilation site. Moreover, in the transmembrane glycoprotein some unique sequence signatures could be detected in the central ectodomain and second heptad repeat (HR2). Some of the mutations affect well-conserved residues, and may affect the conformation and/or the dynamics of envelope glycoproteins complex, including the SU,TM association and the modulation of viral entry function. J. Med. Virol. 81:1869,1881, 2009. © 2009 Wiley-Liss, Inc. [source] Quasispecies analysis of novel HIV-1 recombinants of subtypes A and G reveals no similarity to the mosaic structure of CRF02_AG,JOURNAL OF MEDICAL VIROLOGY, Issue 9 2007Rebecca L.R. Powell Abstract HIV-1 circulating recombinant form (CRF) 02_AG is responsible for greater than 65% of HIV-1 infections in Cameroon and is widespread across West and West-Central Africa. The parental subtypes A1 and G cocirculate in this part of Africa, and high rates of infection predispose to the generation of AG unique recombinant forms (URFs). Little is known as to whether A1 and G can recombine and thrive in vivo with breakpoints other than those characteristic of CRF02_AG. In this study, six unique recombinant viruses of subtypes A1 and G were identified in two individuals in Cameroon. A 1.5 kb fragment of the reverse transcriptase (RT) region of pol (HXB2 location 2,612,4,159) and the entire env gene (HXB2 location 6,202,9,096) were evaluated by phylogenetic and breakpoint analyses. Each URF was found to have breakpoints different than CRF02_AG, indicating that A and G gene segments are functionally compatible with more than one pattern of recombination. Furthermore, contemporaneous, cultured viruses from these individuals were analyzed, revealing different proportions of URFs compared to those found in plasma, possibly indicating compart mentalization and/or phenotypic variation among the URFs. CRF02_AG emerged from West-Central Africa to become a highly successful viral strain. As such, monitoring the spread of newly emerging AG recombinants is critical not only for understanding the epidemiology of HIV-1, but also in the design of future therapeutics and vaccines appropriate to this part of Africa, and globally. J. Med. Virol. 79:1270,1285, 2007. © Wiley-Liss, Inc. [source] Rational development of a HIV-1 gene therapy vectorTHE JOURNAL OF GENE MEDICINE, Issue 10 2003D. S. Anson Abstract Background HIV-1 provides an attractive option as the basis for gene transfer vectors due to its ability to stably transduce non-cycling cell populations. In order to fully utilise the promise of HIV-1 as a vector it is important that the effects of viral cis sequence elements on vector function are carefully delineated. Methods In this study we have systematically evaluated the effect of various cis elements from the HIV-1 YU-2 genome that have been implicated as either affecting vector performance, or HIV-1 replication, on the efficiency of vector production (titre and infectivity). As a measure of the relative safety of vectors their propensity to inadvertently transfer the gagpol gene to transduced cells was assessed. Results Sequences that were found to increase vector titre were from the 5, end of the gag gene, from the 5, and 3, ends of the env gene, from immediately upstream of the polypurine tract, and the central polypurine tract. The substitution of the HIV-1 RRE with heterologous RNA transport elements, or the deletion of the RRE, resulted in greatly reduced vector titres. RNA analysis suggested that the role of the Rev/RRE system extends beyond simply acting as an RNA nuclear export signal. The relative safety of different vector designs was compared and an optimal construct selected. Conclusions Based on our results we have constructed a vector that is both more efficient, and has better safety characteristics, than the widely used pHR, HIV-1 vector construct. Copyright © 2003 John Wiley & Sons, Ltd. [source] An optimized nested polymerase chain reaction (PCR) approach allows detection and characterization of human immunodeficiency virus type 1 (HIV-1) env and gag genes from clinical samplesJOURNAL OF CLINICAL LABORATORY ANALYSIS, Issue 2 2008Dayse Locateli Abstract The needs for development and/or improvement of molecular approaches for microorganism detection and characterization such as polymerase chain reaction (PCR) are of high interest due their sensitivity and specificity when compared to traditional microbiological techniques. Considering the worldwide importance of human immunodeficiency virus type 1 (HIV-1) infection, it is essential that such approaches consider the genetic variability of the virus, the heterogeneous nature of the clinical samples, the existence of contaminants and inhibitors, and the consequent needs for standardization in order to guarantee the reproducibility of the methods. In this work we describe a nested PCR assay targeting HIV-1 virus gag and env genes, allowing specific and sensitive diagnosis and further direct characterization of clinical samples. The method described herein was tested on clinical samples and allowed the detection of HIV-1 presence in all samples tested for the gag gene and 90.9% for the env gene, revealing sensitivities of 1,fg and 100,fg, respectively. Also, no cross-reactions were observed with DNA from infected and noninfected patients and the method allowed detection of the env and gag genes on an excess of 108 and 104 of human deoxyribonucleic acid (DNA), respectively. Furthermore, it was possible to direct sequence all amplified products, which allowed the sub typing of the virus in clinical samples. J. Clin. Lab. Anal. 22:106,113, 2008. © 2008 Wiley-Liss, Inc. [source] Molecular characterization of the env gene of two CCR5/CXCR4-independent human immunodeficiency 2 primary isolates,JOURNAL OF MEDICAL VIROLOGY, Issue 11 2009Quirina Santos-Costa Abstract Human immunodeficiency virus 2 (HIV-2) infection is characterized by a slower disease progression and lower transmission rates. The molecular features that could be assigned as directly involved in this in vivo phenotype remain essentially unknown, and the importance of HIV-2 as a model to understand pathogenicity of HIV infection has been frequently underestimated. The early events of the HIV replication cycle involve the interaction between viral envelope glycoproteins and cellular receptors: the CD4 molecule and a chemokine receptor, usually CCR5 or CXCR4. Despite the importance of these two chemokine receptors in human immunodeficiency virus 1 (HIV-1) entry into cells, we have previously shown that in some HIV-2 asymptomatic individuals, a viral population exists that is unable to use both CCR5 and CXCR4. The goal of the present study was to investigate whether possible regions in the env gene of these viruses might account for this phenotype. From the molecular characterization of these env genes we could not detect any correlation between V3 loop sequence and viral phenotype. In contrast, it reveals the existence of remarkable differences in the V1/V2 and C5 regions of the surface glycoprotein, including the loss of a putative glycosilation site. Moreover, in the transmembrane glycoprotein some unique sequence signatures could be detected in the central ectodomain and second heptad repeat (HR2). Some of the mutations affect well-conserved residues, and may affect the conformation and/or the dynamics of envelope glycoproteins complex, including the SU,TM association and the modulation of viral entry function. J. Med. Virol. 81:1869,1881, 2009. © 2009 Wiley-Liss, Inc. [source] Generation of stable retrovirus packaging cell lines after transduction with herpes simplex virus hybrid amplicon vectors,THE JOURNAL OF GENE MEDICINE, Issue 3 2002Miguel Sena-Esteves Abstract Background A number of properties have relegated the use of Moloney murine leukemia virus (Mo-MLV)-based retrovirus vectors primarily to ex vivo protocols. Direct implantation of retrovirus producer cells can bypass some of the limitations, and in situ vector production may result in a large number of gene transfer events. However, the fibroblast nature of most retrovirus packaging cells does not provide for an effective distribution of vector producing foci in vivo, especially in the brain. Effective development of new retrovirus producer cells with enhanced biologic properties may require the testing of a large number of different cell types, and a quick and efficient method to generate them is needed. Methods Moloney murine leukemia virus (Mo-MLV) gag-pol and env genes and retrovirus vector sequences carrying lacZ were cloned into different minimal HSV/AAV hybrid amplicons. Helper virus-free amplicon vectors were used to co-infect glioma cells in culture. Titers and stability of retrovirus vector production were assessed. Results Simultaneous infection of two glioma lines, Gli-36 (human) and J3T (dog), with both types of amplicon vectors, generated stable packaging populations that produced retrovirus titers of 0.5,1.2×105 and 3.1,7.1×103 tu/ml, respectively. Alternatively, when cells were first infected with retrovirus vectors followed by infection with HyRMOVAmpho amplicon vector, stable retrovirus packaging populations were obtained from Gli-36 and J3T cells producing retrovirus titers comparable to those obtained with a traditional retrovirus packaging cell line, ,CRIPlacZ. Conclusions This amplicon vector system should facilitate generation of new types of retrovirus producer cells. Conversion of cells with migratory or tumor/tissue homing properties could result in expansion of the spatial distribution or targeting capacity, respectively, of gene delivery by retrovirus vectors in vivo. Copyright © 2002 John Wiley & Sons, Ltd. [source] | |||||||||||||