Assignment of the GOV (Glioblastoma overexpressed) gene to human chromosome band 19p13.2 by fluorescence in situ hybridization.
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Chromosome Banding↗
Biomedical subjects
A Sehgal
Publications and source records attributed to A Sehgal.
Lef1 transcription factor expression defines airway progenitor cell targets for in utero gene therapy of submucosal gland in cystic fibrosis.
Cystic fibrosis (CF) has emerged as a paradigm disorder for assessing the utility of gene therapy in the treatment of genetic diseases. It is hypothesized that submucosal glands may play an important role in the pathophysiology of CF lung disease. However, this region poses several significant obstacles for gene therapy due to its inaccessibility from the lumen of adult proximal airways. In utero gene therapy to correct submucosal gland dysfunction in CF provides an attractive alternative strategy to target gland progenitor cells prior to gland formation and morphogenesis. Such approaches will require the use of integrating vectors capable of transducing expanding stem-cell/progenitor-cell populations in the lung. We described a newborn-ferret model of the proximal airway which was used to evaluate the phenotypic characteristics of submucosal gland progenitors and to test gene therapy strategies for targeting these cell types. To this end, we have isolated the ferret cDNA to the lymphoid enhancing factor 1 (Lef1) and have demonstrated that its mRNA expression specifically defines a subset of surface airway epithelial progenitor cells involved in the formation of primordial submucosal gland buds and subsequent gland morphogenesis. Such findings suggest that the transcriptional switch regulating activation of Lef1 expression defines the phenotype of early submucosal gland progenitor cells. In an effort to prove the principle of gene targeting to this progenitor-cell population, we evaluated the efficiency of recombinant retroviral vectors to target submucosal glands in a xenograft model system. Findings from these studies demonstrated successful gene targeting to progenitor cells of submucosal gland buds which was stable throughout subsequent gland development. In summary, these studies have provided evidence for the existence of phenotypically distinct submucosal gland progenitor cells which represent appropriate targets for gene therapy of submucosal glands in CF.
Amino Acid Sequence↗
Alterations of per RNA in noncoding regions affect periodicity of circadian behavioral rhythms.
Circadian rhythms in Drosophila depend on a molecular feedback loop that includes products of the period (per) and timeless (tim) genes. RNA and protein products of both genes cycle with a circadian period and the proteins feedback to inhibit expression of their own mRNAs. While cyclic expression of PER protein appears to be necessary for rhythmic behavior, the function of per RNA cycling is somewhat controversial. Rhythmic transcription accounts, in part, for cycling of per RNA, but it is clear now that posttranscriptional mechanisms also contribute to the cyclic expression of both per RNA and protein. As posttranscriptional mechanisms, such as mRNA stability and translation, are frequently mediated by 3' untranslated regions (UTR) of genes, the authors examined the role of this region of per in the regulation of circadian rhythms. Removal of most of per's 3' UTR had a small effect on the function of a per transgene. However, replacement of per's 3'UTR with corresponding sequences of the tubulin gene led to the rescue of behavioral rhythms in per01 flies with periods that were 3 h shorter than those generated by a wild-type per transgene. The hybrid RNA cycles, but the protein produced by it accumulates earlier in a day-night cycle than the PER protein produced by a control per transgene carrying its own 3'UTR, perhaps because the tubulin sequences counteract the effect of destabilizing elements in the per RNA at earlier points in the circadian cycle. These data indicate that the appropriate regulation of per RNA expression, effected by transcriptional as well as posttranscriptional mechanisms, is critical for the determination of circadian period.
Animals↗
Isolation and characterization of a novel gene from human glioblastoma multiforme tumor tissue.
Using the technique of DD-PCR (differential display-polymerase chain reaction) we isolated a novel gene (D2-2) that is overexpressed in glioblastoma multiforme tissue (GMT) as compared to normal brain tissue (NBT). D2-2 is also highly expressed in recurrent glioma, colon tumor metastatic to brain, breast tumors, prostate tumors and a prostate tumor cell line (LNCaP). Northern blot analysis showed that D2-2 is highly expressed in several tumor cell lines (MOLT lymphoblastic leukemia, SW480 colorectal adrenocarcinoma, A549 lung carcinoma, HL-60 promyelocytic leukemia, S3 HeLa cells, K-562 chronic myelogeneous leukemia and G361 melanoma) as compared to NBT. Additionally, D2-2 is very highly expressed in cell lines derived from glioblastomas, grade IV astrocytomas, normal human fetal astrocytes (NHFA) and glioma. D2-2 is moderately expressed in neuroblastoma, neuroectodermal and medulloblastoma tumor cell lines. D2-2 expression is localized to the frontal lobe, occipital lobe and the cerebellum in the normal brain. Normal tissues such as thyroid, stomach, adrenal cortex, small intestine and pancreas show high expression of D2-2. We also show that D2-2 is expressed 28-fold higher in fetal brain (20 weeks) than in adult brain. Sequence analysis of a 2.0-kb fragment for D2-2 shows no homology to known sequences in the data base.
Amino Acid Sequence↗
Characterization of C4-2 as a tumor-suppressor gene in human brain tumors.
BACKGROUND: Brain tumors claimed the lives of 13,300 people in 1995. Our objective was to isolate and characterize unique tumor-suppressor genes from human brain tumors derived from patients in the United States. METHODS: Differential display-polymerase chain reaction was used to isolate tumor suppressor genes. RESULTS: Clone C4-2 was isolated and is expressed in normal adult human brain, but not in brain tissue from glioblastoma multiforme tumors. C4-2 has 66% homology to the previously isolated ARPP-16 (cAMP-regulated phosphoprotein of Mr = 16,000) based on limited sequencing. C4-2 is expressed at high levels in normal brain and is not expressed or expressed at low levels in several brain tumor cell lines. Expression of C4-2 was also either not expressed or expressed at low levels in meningioma, B-cell lymphoma, recurrent glioma, LNCAP (prostate tumor cell line), breast tumor, or prostate tumor tissue. CONCLUSION: We conclude that C4-2 may function as a potential tumor-suppressor gene.
Adult↗
Cloning, sequence, and developmental expression analysis of C4-2, a potential brain tumor-suppressor gene.
BACKGROUND: Previously, we reported the isolation of C4-2 as a potential tumor suppressor gene in human brain tumors. To understand the function of this gene, we investigated its molecular characterization and expression during development. METHODS: Human fetal brain library screening and 5'RACE-PCR method was used to isolate the full-length cDNA. The coding region of C4-2 was used for in situ hybridization to study its expression during development. RESULTS: We report here the complete sequence of this gene. Sequence analysis indicated that C4-2 has a 94% sequence identity to a family of cAMP-regulated phosphoproteins (ARPP-16/19) in the coding region. C4-2 has a 3.1 Kb long 3'UTR with variable identity to ARPP-16 and ARPP-19. Northern blot analysis indicated that C4-2 is expressed at high levels in normal brain compared to other tissues. Zoo blot analysis demonstrated that the coding region of C4-2 is highly conserved among different animals. In situ hybridization using C4-2 coding region demonstrated that it follows a unique expression pattern during mouse brain development. High level of C4-2 expression was also observed in the spinal cord and somites of the developing embryo. CONCLUSION: Expression analysis during brain development strongly suggests that this family of proteins may play an important role not only in normal functioning of the brain, but also during brain development.
Amino Acid Sequence↗
Differentially regulated epithelial expression of an Eph family tyrosine kinase (fHek2) during tracheal surface airway and submucosal gland development.
A ferret model was used to evaluate the potential role of an Eph family tyrosine kinase (fHek2) in tracheal development of surface airway epithelium and submucosal glands. A partial 2.6-kb cDNA fragment of fHek2 was isolated from a ferret tracheal/lung cDNA library. Sequence analysis demonstrated that this gene is the ortholog to the previously cloned human Hek2 gene. In situ hybridization analysis of fHek2 mRNA expression on ferret tracheal developmental time points revealed an expression pattern within a subset of surface airway epithelial cells which remained relatively constant throughout tracheal development (from -2 d in utero to adult). In contrast, developing tracheal submucosal glands at 3-day postnatal time points demonstrated little fHek2 mRNA expression. However, expression of fHek2 significantly increased more than 4-fold over the course of gland development to adulthood. These findings, which demonstrate a uniquely regulated pattern of fHek2 mRNA expression between surface airway epithelium and submucosal glands, have implications on regulatory processes which control differentiation and/or maturation of secretory structures in the lung. Such findings may be useful in further delineating the mechanisms which control cellular differentiation in the lung and how these processes are abnormally regulated in hypersecretory diseases such as chronic bronchitis, asthma, and cystic fibrosis.
Amino Acid Sequence↗
Regulation of the Drosophila protein timeless suggests a mechanism for resetting the circadian clock by light.
Circadian behavioral rhythms in Drosophila depend on the appropriate regulation of at least two genes, period (per) and timeless (tim). Previous studies demonstrated that levels of PER and TIM RNA cycle with the same phase and that the PER and TIM proteins interact directly. Here we show the cyclic expression of TIM protein in adult heads and report that it lags behind peak levels of TIM RNA by several hours. We alsoshow that nuclear expression of TIM depends upon the expression of PER protein. Finally, we report that the expression of TIM, but not PER, is rapidly reduced by light, suggesting that TIM mediates light-induced resetting of the circadian clock. Since both PER and TIM RNA are unaffected by light treatment, the effects of light on TIM appear to be posttranscriptional.
Animals↗
Isolation and cloning of JTAP-1: a cathepsin like gene upregulated in response to V-Jun induced cell transformation.
The oncogenic potential of Jun in chicken embryo fibroblasts (CEF) varies depending on its structure. V-Jun, which has a number of structural differences from c-Jun is highly transforming and tumorigenic. C-Jun however, is only weakly transforming and is not tumorigenic. We have used this difference in oncogenic potential between v-Jun and c-Jun to screen for downstream target genes associated with the v-Jun induced transformed phenotype. We describe here the identification, cloning and characterization of one of these genes, JTAP-1. JTAP-1 is consistently overexpressed 7 to 10-fold in CEF transformed by v-Jun compared with c-Jun overexpressing or normal CEF. This pattern of expression suggests that JTAP-1 is associated with the transformed phenotype. DNA and amino acid homology search analysis revealed that JTAP-1 shares a high degree of similarity with over 100 cysteine proteases from a variety of species and is likely the chicken homolog of cathepsin O. Analysis of expression of JTAP-1 in CEF overexpressing other oncogenes including v-Ha-ras, v-Src, c-Fos, and Myc revealed that it's overexpression is unique to v-Jun transformed cells. Thus, JTAP-1 is likely a specific target of v-Jun overexpression and not simply a consequence of cell transformation.
Amino Acid Sequence↗
Control of circadian rhythms by a two-component clock.
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Animals↗
Developmental expression patterns of CFTR in ferret tracheal surface airway and submucosal gland epithelia.
Submucosal glands are a major site of cystic fibrosis transmembrane conductance regulator (CFTR) expression in the human airway and may play an important role in the pathogenesis of cystic fibrosis. In humans, strategies for gene targeting to submucosal glands will likely be dependent on in utero gene transfer to submucosal gland progenitors because of the inaccessibility of these regions from the fully developed airway. However, little is known about the ontogeny of CFTR gene expression in developing submucosal glands and the potential functional role(s) CFTR may have during gland development. To this end, we describe the partial cloning of the ferret CFTR cDNA which was used for in situ mRNA localization studies in developing ferret trachea. The ferret animal model is attractive for studies pertaining to the development of tracheal submucosal glands because postnatal tracheal development in this species mirrors in utero gland development in humans. Sequence analysis of the first nucleotide binding domain (NBD1) from ferret CFTR revealed a striking homology to the human gene at both the DNA (94.4%) and amino acid level (97%). Interestingly, this high level of amino acid homology extends to a group of mammalian species (ferret, human, sheep, and bovine) which have similar lung morphologies with respect to the presence of surface airway goblet cells and submucosal glands. In contrast, mouse and rat airways which are quite divergent from those of ferret, human, sheep, and bovine species with respect to secretory cell types in the airway and abundance of submucosal glands, demonstrate significantly less homology (80%) with respect to CFTR amino acid sequence in the NBD1 domain. Given that traditional phylogenetic classification of these species does not mirror the evolutionary conservation of CFTR, such findings would suggest that certain aspects of lung morphology may be reflected in the evolutionary conservation of CFTR NBD1 amino acid sequences. CFTR in situ hybridization studies in ferret trachea demonstrate a developmental increase (3-4 fold) in CFTR mRNA expression within the surface airway epithelium between -2 day to 5 wk which mirrors an increase in ciliogenesis over this time frame. Additionally, all stages of gland development including the most primordial gland-forming buds could be seen to contain infrequent cells which highly express CFTR at a level that remained constant throughout development. Such findings suggest that differentiation of gland progenitor cells to CFTR-expressing submucosal gland cells occurs very early within submucosal gland development and morphogenesis.
Amino Acid Sequence↗
Mutagenicity of endocervical mucus associated with genital tract infections.
Mutagenic metabolites produced due to chronic infection of cervical epithelium are suspected to be a plausible risk factor in cervical carcinogenesis. One hundred twenty-four symptomatic women attending a maternal and child health (MCH) clinic were studied clinically, cytologically, microbiologically, and biochemically for genital tract infections and for the presence of mutagens in the endocervical secretions using Ames' test. Human papillomavirus (HPV) was the leading infection (53.3%), followed by chlamydial infection (25.8%) and seropositivity for herpes simplex virus (25.1%). Mutagenic products in the endocervical secretions was detected in 23 women (18.5%). The univariate and multivariate (adjusted for other genital infections, age, and parity) analysis showed that the mutagenic mucus was associated with only chlamydial infection of endocervical region (OR = 3.7; 95% CI = 1.7,7.3). This shows that chlamydia is associated with mutagenicity of endocervical mucus.
Cervix Mucus↗
Colposcopy as a tool for detection of human papillomavirus infection of uterine cervix in the setting of high prevalence of gynaecologic infections.
A cross sectional study involving 257 women from the Maternal and Child Health Centre (MCH) in Delhi was initiated for screening clinically, cytologically, colposcopically, and microbiologically for several gynaecologic infections. Eighty percent of the women had one or more gynaecologic infections and 31.1% had three or more infections. Cytology revealed changes suggestive of condyloma in 3 (1.2%) women only, while colposcopic examination suggested HPV changes in 117 (45.5%) women. A very high proportion of colposcopically detected lesions (78.6%) had evidence of HPV related changes in histology. The specificity of these lesions were further confirmed by Pan HPV DNA in-situ hybridisation, when 84% of the colposcopy is a valuable tool for detecting subclinical HPV lesions in a setting with high prevalence of gynaecologic infections.
Colposcopy↗
Positional cloning and sequence analysis of the Drosophila clock gene, timeless.
The Drosophila genes timeless (tim) and period (per) interact, and both are required for production of circadian rhythms. Here the positional cloning and sequencing of tim are reported. The tim gene encodes a previously uncharacterized protein of 1389 amino acids, and possibly another protein of 1122 amino acids. The arrhythmic mutation tim01 is a 64-base pair deletion that truncates TIM to 749 amino acids. Absence of sequence similarity to the PER dimerization motif (PAS) indicates that direct interaction between PER and TIM would require a heterotypic protein association.
Amino Acid Sequence↗
Rhythmic expression of timeless: a basis for promoting circadian cycles in period gene autoregulation.
The clock gene timeless (tim) is required for circadian rhythmicity in Drosophila. The accumulation of tim RNA followed a circadian rhythm, and the phase and period of the tim RNA rhythm were indistinguishable from those that have been reported for per. The tim RNA oscillations were found to be dependent on the presence of PER and TIM proteins, which demonstrates feedback control of tim by a mechanism previously shown to regulate per expression. The cyclic expression of tim appears to dictate the timing of PER protein accumulation and nuclear localization, suggesting that tim promotes circadian rhythms of per and tim transcription by restricting per RNA and PER protein accumulation to separate times of day.
Animals↗
Isolation of timeless by PER protein interaction: defective interaction between timeless protein and long-period mutant PERL.
The period (per) gene likely encodes a component of the Drosophila circadian clock. Circadian oscillations in the abundance of per messenger RNA and per protein (PER) are thought to arise from negative feedback control of per gene transcription by PER. A recently identified second clock locus, timeless (tim), apparently regulates entry of PER into the nucleus. Reported here are the cloning of complementary DNAs derived from the tim gene in a two-hybrid screen for PER-interacting proteins and the demonstration of a physical interaction between the tim protein (TIM) and PER in vitro. A restricted segment of TIM binds directly to a part of the PER dimerization domain PAS. PERL, a mutation that causes a temperature-sensitive lengthening of circadian period and a temperature-sensitive delay in PER nuclear entry, exhibits a temperature-sensitive defect in binding to TIM. These results suggest that the interaction between TIM and PER determines the timing of PER nuclear entry and therefore the duration of part of the circadian cycle.
Animals↗
Cavernous hemangioma of the uterus.
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Adolescent↗
Clinical presentation of gynecologic infections among Indian women.
OBJECTIVE: To study the clinical presentation of different gynecologic infections among Indian women. METHODS: This was a cross-sectional study of 257 women that included clinical, cytologic, colposcopic, and microbiologic screening for various gynecologic infections. RESULTS: Human papillomavirus (HPV) was the leading infection, affecting 127 (49.4%) women; however, overt warts were only seen in seven (2.7%) patients. Women infected with HPV had a 60.3-fold higher risk of developing a bleeding ectopia compared to those with other infections; women with an unhealthy cervix and cervical ectopias also had an increased risk of HPV infection (7.6- and 2.8-fold, respectively). Bacterial vaginosis, detected in 33.5% of the women studied, had an increased risk of bleeding ectopia (9.3-fold), cervical ectopia (3.1-fold), cervicitis (2.9-fold), vaginitis (6.9-fold), and cervical hypertrophy (2.1-fold). Chlamydial infection, detected in 23.3% of the patient population, was associated with an eightfold increase in the risk of an unhealthy cervix and a fourfold increase in risk of a hypertrophied cervix. Immunoglobulin-A antibodies to the herpes simplex virus were detected in 53 (20.6%) women. More than half (55.2%) of the women had two or more infections, and the mean delay of seeking medical treatment was 7-13 months. CONCLUSION: The specific finding of bleeding cervices was associated with HPV and bacterial vaginosis, hypertrophied cervices with chlamydia and bacterial vaginosis, and unhealthy cervices with chlamydia and HPV infections.
Adult↗