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Zhou J, Ng AY, Tymms MJ, Jermiin LS, Seth AK, Thomas RS, Kola I. A novel transcription factor, ELF5, belongs to the ELF subfamily of ETS genes and maps to human chromosome 11p13-15, a region subject to LOH and rearrangement in human carcinoma cell lines. Oncogene 1998; 17:2719-32. [PMID: 9840936 DOI: 10.1038/sj.onc.1202198] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The ETS transcription factors are a large family implicated in the control of cellular proliferation and tumorigenesis. In addition, chromosomal translocations involving ETS family members are associated with a range of different human cancers. Given the extensive involvement of ETS factors in tumorigenesis, it becomes important to identify any additional ETS genes that may also play oncogenic roles. We identify a novel gene, ELF5, that appears to belong to the ELF (E74-like-factor) subfamily of the ETS transcription factor family, based upon similarity within the 'ETS domain'. ELF5 displays a similar, but more restricted, expression pattern to that of the newly isolated epithelium-specific ETS gene, ELF3. Unlike most other ETS family members, ELF5 is not expressed in hematopoietic compartments, but is restricted to organs such as lung, stomach, kidney, prostate, bladder and mammary gland. ELF5 is localized to human chromosome 11p13-15, a region that frequently undergoes loss of heterozygosity (LOH) in several types of carcinoma, including those of breast, kidney and prostate. We find that ELF5 expression is not detectable in a number of carcinoma cell lines, some of which display loss or rearrangement of an ELF5 allele. Similar to other ETS family members, ELF5 displays specific binding to DNA sequences containing a GGAA-core. In addition, ELF5 is able to transactivate through these ETS sequences, present upstream from a minimal promoter. Our data suggest that ELF5 may play roles in mammary, lung, prostate and/or kidney function, and possibly also in tumorigenesis.
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Seth AK, Nijhawan VS, Bhandari MK, Dhaka RS, Kochar SK. GASTRIC TUBERCULOSIS: A Case Report. Med J Armed Forces India 1998; 54:278-279. [PMID: 28775500 DOI: 10.1016/s0377-1237(17)30568-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
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Dhiman RK, Seth AK, Jain S, Chawla YK, Dilawari JB. Prognostic evaluation of early indicators in fulminant hepatic failure by multivariate analysis. Dig Dis Sci 1998; 43:1311-6. [PMID: 9635624 DOI: 10.1023/a:1018876328561] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Viral hepatitis is the commonest cause of fulminant hepatic failure (FHF) in developing countries. We evaluated the early indicators of prognosis in these patients by multivariate analysis. The records of 204 consecutive patients with acute liver failure admitted with hepatic encephalopathy over five years were studied. The etiology of these patients included virus related in 186 (91.1%), drug induced in 15 (7.4%), Wilson's disease in one (0.5%), acute Budd-Chiari syndrome in one (0.5%), and malignant infiltration in one (0.5%). Patients with FHF complicating viral hepatitis were analyzed by univariate and multivariate analysis. These patients were further subclassified depending upon the interval between the onset of jaundice and the onset of encephalopathy into hyperacute (HALF; interval 0-7 days), acute (ALF; interval 8-28 days) and subacute liver failure (SALF; interval 4-12 weeks). Sixty (32.3%) patients with viral hepatitis survived. Univariate analysis showed that the interval between onset of encephalopathy and onset of jaundice, grade of encephalopathy, raised intracranial pressure, prothrombin time, and serum bilirubin levels on admission were related to outcome in these patients. Multivariate logistic regression analysis showed that the presence of raised intracranial pressure at the time of admission, prothrombin time >100 sec on admission, age (>50 yr), and onset of encephalopathy seven days after onset of jaundice were associated with poor prognosis. Forty seven (37.0%) of 129 patients with HALF survived compared with 9 (22.5%) of 40 with ALF and 4 (21.1%) of 19 with SALF (P = NS). Raised intracranial pressure was more frequent in patients with HALF (48.8%) than in patients with ALF (32.5%) and SALF (15.8%; P = 0.01), while clinically detectable ascites was more frequent in patients with SALF (78.9%) compared with HALF (19.7%) and ALF (37.5%; P < 0.0001). The factors adversely affecting the outcome in our patients with FHF complicating viral hepatitis include presence of overt clinical features of raised ICP at the time of hospitalization, prothrombin time (>100 sec) on admission, age (>50 yr), and onset of encephalopathy seven days after onset of jaundice.
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Harris GJ, Garcia GH, Logani SC, Murphy ML, Sheth BP, Seth AK. Orbital blow-out fractures: correlation of preoperative computed tomography and postoperative ocular motility. TRANSACTIONS OF THE AMERICAN OPHTHALMOLOGICAL SOCIETY 1998; 96:329-47; discussion 347-53. [PMID: 10360296 PMCID: PMC1298402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
BACKGROUND/PURPOSE Although the management of orbital blow-out fractures was controversial for many years, refined imaging with computed tomography (CT) helped to narrow the poles of the debate. Many orbital surgeons currently recommend repair if fracture size portends late enophthalmos, or if diplopia has not substantially resolved within 2 weeks of the injury. While volumetric considerations have been generally well-served by this approach, ocular motility outcomes have been less than ideal. In one series, almost 50% of patients had residual diplopia 6 months after surgery. A fine network of fibrous septa that functionally unites the periosteum of the orbital floor, the inferior fibrofatty tissues, and the sheaths of the inferior rectus and oblique muscles was demonstrated by Koornneef. Entrapment between bone fragments of any of the components of this anatomic unit can limit ocular motility. Based on the pathogenesis of blow-out fractures, in which the fibrofatty-muscular complex is driven to varying degrees between bone fragments, some measure of soft tissue damage might be anticipated. Subsequent intrinsic fibrosis and contraction can tether globe movement, despite complete reduction of herniated orbital tissue from the fracture site. We postulated that the extent of this soft tissue damage might be estimated from preoperative imaging studies. METHODS Study criteria included: retrievable coronal CT scans; fractures of the orbital floor without rim involvement, with or without extension into the medial wall; preoperative diplopia; surgical repair by a single surgeon; complete release of entrapped tissues; and postoperative ocular motility outcomes documented with binocular visual fields (BVFs). Thirty patients met all criteria. The CT scans and BVFs were assessed by different examiners among the authors. Fractures were classified into 3 general categories and 2 subtypes to reflect the severity of soft tissue damage within each category. "Trap-door" injuries, in which bone fragments appeared to have almost perfectly realigned, were classified as type I fractures. In the I-A subtype, no orbital tissue was visible on the sinus side of the fracture line. In the I-B subtype, soft tissue with the radiodensity of orbital fat was visible within the maxillary sinus. In type II fractures, bone fragments were distracted and soft tissue was displaced between them. In the II-A subtype, soft tissue displacement was less than, or proportional to, bone fragment distraction. In the II-B subtype, soft tissue displacement was greater than bone fragment distraction. In type III fractures, displaced bone fragments surrounded displaced soft tissue in all areas. In the III-A subtype, soft tissue and bone were moderately displaced. In the III-B subtype, both were markedly displaced. Motility outcomes were quantified by measuring the vertical excursion in BVFs. The interval between trauma and surgical repair was also determined. RESULTS Among the 15 patients with a motility outcome in BVFs which was poorer than the median (86 degrees or less of single binocular vertical excursion), 4 patients (27%) had type A fractures; 11 patients (73%) had type B fractures. Among the 15 patients with a better outcome than the median (88 degrees or more), 10 patients (67%) had type A fractures; 5 patients (33%) had type B fractures. These differences became more defined as analysis moved away from the median. Among 5 patients with type B fractures and better than the median result in BVFs, 3 patients (60%) had surgical repair during the first week after injury. Among the 11 patients with type B fractures and less than the median result, 1 patient (9%) had repair during the first week. CONCLUSIONS When the CT-depicted relationship between bone fragments and soft tissues is considered, a wide spectrum of injuries is subsumed under the rubric of blow-out fractures. In general, greater degrees of soft tissue incarceration or displacement, with presumably greater intrinsic damage and subsequent fibrosis, appear to result in poorer motility outcomes. Although this retrospective study does not conclusively prove its benefit, an urgent surgical approach to selected injuries should be considered.
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Seth AK, Dhiman RK, Gupta S, Gulati M, Chawla YK, Suri S, Dilawari JB. Combined percutaneous-endoscopic approach for biliary endoprosthesis placement. Indian J Gastroenterol 1997; 16:149-50. [PMID: 9357188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
A nonoperative method of palliation was used in four patients with malignant obstructive jaundice in whom biliary endoprosthesis could not be placed endoscopically. A guide wire was manipulated through the lesion by a percutaneous transhepatic route and retrieved from the duodenum through an endoscope. A 10 Fr stent was then passed through the endoscope over the guide wire across the stricture. The procedure was successful in all four patients, with no complication.
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Seth AK, Chawla Y, Dhiman RK, Gupta S, Suri S, Dilawari JB. Caroli's disease: a central dot means a lot. TROPICAL GASTROENTEROLOGY : OFFICIAL JOURNAL OF THE DIGESTIVE DISEASES FOUNDATION 1997; 18:165-6. [PMID: 9612099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
We present here a patient of congenital non-obstructive focal dilatation of intrahepatic biliary radicles (Caroli's disease). The peculiar configuration of dilated intrahepatic biliary channels with central portal vein radicles was picked up sonologically as the 'central dot' sign. Awareness of this sign allows an accurate diagnosis without resorting to more invasive and expensive investigations.
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Gupta SK, Gupta RC, Seth AK, Gupta A. Reversal of fluorosis in children. ACTA PAEDIATRICA JAPONICA : OVERSEAS EDITION 1996; 38:513-9. [PMID: 8942013 DOI: 10.1111/j.1442-200x.1996.tb03536.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Large populations consume fluoride-contaminated water, especially in developing countries. The toxic effects of fluorosis take three forms: clinical, skeletal and dental. Research thus far indicates that the manifestations of fluorosis are irreversible. However, it has been observed that the ingestion of calcium, vitamin C or vitamin D, individually, is effective in protection from fluoride toxicity to a certain extent. Therefore, a double blind control trial was conducted to examine the effect of a combination of calcium, vitamin D3 and ascorbic acid supplementation in fluorosis-affected children. In the present study, 25 children were selected from an area consuming water containing 4.5 p.p.m. of fluoride, All the children were in the age group 6-12 years and weighed 18-30 kg. They were graded for clinical, radiological and dental fluorosis and relevant biochemical parameters. Grade I skeletal fluorosis and all grades of the manifestation of dental and clinical fluorosis were observed. The children were given ascorbic acid, calcium and vitamin D3 well below the toxic dosages in a double blind manner using lactose as a placebo. Follow up revealed a significant improvement in dental, clinical and skeletal fluorosis and relevant biochemical parameters in these children. Thus, the study indicated that fluorosis can be reversed, at least in children, by a therapeutic regimen that is fairly cheap, simple and easily available and without any side effects.
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Westbrook RF, Duffield TQ, Good AJ, Halligan S, Seth AK, Swinbourne AL. Extinction of within-event learning is contextually controlled and subject to renewal. THE QUARTERLY JOURNAL OF EXPERIMENTAL PSYCHOLOGY. B, COMPARATIVE AND PHYSIOLOGICAL PSYCHOLOGY 1995; 48:357-375. [PMID: 8532900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Five experiments examined within-event learning in rats by inducing an appetite for one of the elements (salt) of a compound stimulus and assessing preference for the other element (almond). Almond preference was conditional upon (1) the almond flavour having been presented in compound with the salt, and (2) the assessment being conducted when the rats were out of sodium balance (Experiment 1). Presentations of the compound in one environment (A) and of the salt and almond elements in a second environment (B) resulted in greater almond preference when rats were tested in A than in B (Experiment 2). Almond preference was reduced when separate presentations of the compound and almond (Experiment 3) or of the compound and salt (Experiment 4) occurred in the same environments but not when these presentations occurred in different environments. Rats exposed to the compound in A and then extinguished to the elements in either A or B showed a reduced almond preference when tested in the extinction environment, but not when tested in the other environment (Experiment 5). Thus, extinction of within-event learning is context-specific and subject to renewal. The results were interpreted in terms of an associative model whereby separate presentations of the elements result in a symmetrical inhibitory link which is contextually gated (Bouton, 1993).
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Gupta SK, Gupta RC, Seth AK, Chaturvedi CS. Increased incidence of spina bifida occulta in fluorosis prone areas. ACTA PAEDIATRICA JAPONICA : OVERSEAS EDITION 1995; 37:503-6. [PMID: 7572153 DOI: 10.1111/j.1442-200x.1995.tb03363.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Spina bifida, a congenital deformity of the posterior wall of vertebrae of the spine, is a midline defect of skin, vertebral arches and neural tube, usually in the lumbosacral region. Its incidence is reported to be 0.2 to 0.4 per 1000 live births. Various hypotheses have been put forward as etiological factors for spina bifida including consumption of potato affected by blight and hardness of drinking water but these have not been proven. Two groups of 50 randomly chosen children were established. The study group consisted of children aged 5 to 12 years, weighing 15 to 30 kg, consuming fluoride rich drinking water (4.5 and 8.5 ppm fluoride; WHO permissible limit is 1.5 ppm fluoride), and manifesting either clinical, dental and/or skeletal fluorosis. The control group consisted of age and weight-matched children, consuming less than or equal to 1.5 ppm fluoride in drinking water and not showing any evidence of fluoride toxicity. These children were evaluated for antenatal history, general clinical examination (especially for dimples, tufts of hair, haemangioma on skin throughout the length of spine), other congenital abnormalities, evidence of fluoride toxicity, biochemical estimation for fluoride levels in blood and serum and by skiagrams of the spine to examine for the presence of spina bifida occulta. A total of 22 (44%) of the 50 children in group A, the study group, and 6 (12%) of the 50 children in group B, the control group, revealed spina bifida occulta in the lumbosacral region.(ABSTRACT TRUNCATED AT 250 WORDS)
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Gupta SK, Gupta RC, Seth AK. Increased incidence of spina bifida occulta in fluorosis prone areas. Indian Pediatr 1994; 31:1431-2. [PMID: 7896351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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Gupta SK, Gupta RC, Seth AK. Reversal of clinical and dental fluorosis. Indian Pediatr 1994; 31:439-43. [PMID: 7875866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
A large number of Indians are forced to consume fluoride contaminated water. Toxic effects of chronic fluoride ingestion are hitherto considered irreversible. In this study 20 children were selected from an area consuming water containing 4.5 ppm of fluoride (Group A) and a second sample of 20 children from another area consuming water containing 8.5 ppm of fluoride (Group B). All the children were in an age group of 3 to 12 years and weighed 12 to 25 kg. Both samples were graded for clinical, radiological and dental fluorosis. All grades of manifestations were observed. These children were given ascorbic acid (500 mg), calcium (250 mg) and vitamin D3 (800 IU) daily. Follow up revealed reversal of clinical and dental fluorosis after 44 days. Improvement in the Group B sample was slower than Group A. Dosage of ascorbic acid was increased to 750 mg per day, keeping the dosages of other drugs unchanged to Group B children. After 15 days of the revised therapy a marked improvement was noticed in clinical and dental fluorosis in this sample also.
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Abstract
Transplacental passage of fluorides was studied in 25 randomly selected neonates. Blood samples collected simultaneously from the mother and the umbilical cord showed that average fluoride concentration in the cord blood was 60% of that in mother's blood. When concentration in the mother's blood exceeded 0.4 ppm, the placenta acted as a selective barrier.
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Chen ZQ, Burdett LA, Seth AK, Lautenberger JA, Papas TS. Requirement of ets-2 expression for Xenopus oocyte maturation. Science 1990; 250:1416-8. [PMID: 2255913 DOI: 10.1126/science.2255913] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A molecular clone of the Xenopus laevis ets-2 gene was isolated from an oocyte complementary DNA library. The amount of messenger RNA (mRNA) in each oocyte or embryo was almost constant during oogenesis and was maintained until the blastula stage of embryonic development, indicating that the observed 3.2-kilobase transcript is a maternal message. The only normal adult tissue in which ets-2 mRNA was detected was the ovary. Injection of antisense oligonucleotides homologous to the ets-2 sequence into oocytes led to degradation of the mRNA and blocked hormone-induced germinal vesicle breakdown. The ets-2 product is thus required for the meiotic maturation of Xenopus oocytes.
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Samuel KP, Ascione R, Kottaridis SD, Seth AK, Lautenberger JA, Zuber M, Strouboulis J, Papas TS. Expression of animal and human retroviral gene products in Escherichia coli with the lambda PL promoter pJL6 vector system. GENETIC ANALYSIS, TECHNIQUES AND APPLICATIONS 1990; 7:178-208. [PMID: 2150172 DOI: 10.1016/0735-0651(90)90023-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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165
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Seth AK, McWilliams BJ. Weight gain in children with cleft palate from birth to two years. THE CLEFT PALATE JOURNAL 1988; 25:146-50. [PMID: 3163290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The weights from birth to 2 years of 77 babies with palatal clefts were compared with the weights of normal babies (Pomerance, 1979). Babies with clefts did not differ from normal infants in mean birth weight, but they lagged behind thereafter. Males were more impaired than females.
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Jay E, Seth AK, Rommens J, Sood A, Jay G. Gene expression: chemical synthesis of E. coli ribosome binding sites and their use in directing the expression of mammalian proteins in bacteria. Nucleic Acids Res 1982; 10:6319-29. [PMID: 6294598 PMCID: PMC326921 DOI: 10.1093/nar/10.20.6319] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Mammalian genes, when inserted into bacterial plasmid or phage DNAs, will not be expressed into the corresponding specific proteins in E. coli unless proper initiations signals required for recognition by E. coli ribosomes are provided. We have studied these signals and chemically synthesized two DNA duplexes each containing different initiation signals. These have been inserted in front of the Simian virus 40 (SV40) small tumor antigen gene (SV40 t gene) at varying distances from the ATG initiation codon prior to its cloning into pBR322 plasmid DNA. Plasmid containing clones carrying either of these two synthetic ribosome binding sites (RBS) at varying distances from the SV40 t gene all produced a 17K protein identical to authentic t antigen by immunologic, electrophoretic and proteolytic digestion analyses. This provides a novel method to ensure the specific expression of any contiguous mammalian gene to be cloned to bacteria, and also a unique in vivo method for studying the structure-function (efficiency) relationship of RBS with specific base changes.
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Vlietstra RE, Kronmal RA, Frye RL, Seth AK, Tristani FE, Killip T. Factors affecting the extent and severity of coronary artery disease in patients enrolled in the coronary artery surgery study. ARTERIOSCLEROSIS (DALLAS, TEX.) 1982; 2:208-15. [PMID: 6979996 DOI: 10.1161/01.atv.2.3.208] [Citation(s) in RCA: 73] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
This study was designed to test the relationship between each of nine risk variables and the extent and severity of coronary artery disease in 15,298 patients with coronary artery disease proven by arteriography who were enrolled in the Coronary Artery Surgery Study. The extent and severity of the disease were highly significantly (p less than 0.001), but modestly, correlated with age, sex, cholesterol levels, history of diabetes, and history of hypertension. Interestingly, no positive correlation (indeed, in some subgroups, a negative correlation) occurred between the arteriographic measures of disease and the cigarette smoking history (ever or never, number of pack-years of smoking, duration of cigarette smoking, and peak daily cigarette consumption). These results suggest that the risk factors for presence of disease may differ from those influencing angiographic extent and severity.
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Vlietstra RE, Kronmal RA, Seth AK, Frye RL. [Correlation of the coronary heart disease risk factors and coronary angiographic data]. KARDIOLOGIIA 1982; 22:67-72. [PMID: 7069990] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The findings for 14 risk variables were correlated with the results of coronary angiography in 8807 patients enrolled in the multicenter Coronary Artery Surgery Study. Discriminant function analysis revealed that age, sex, cigarette smoking and level of blood cholesterol best distinguished between the groups with (6688 patients) and without (2119 patients) coronary artery disease (CAD). The relative risk for CAD in patients with the combination of cigarette smoking and an elevated cholesterol level was high in women 55 years old or younger and in men 35 years old or younger. Few women 45 years old or younger (7 out of 97) had CAD when neither of these risk factors were present. Despite these correlations, only limited gains accrued from the use of discriminant function analysis in correctly allocating patients into disease and nondisease groups. Extent and severity of disease in 15298 patients with CAD were significantly (p less than 0.001) but modestly correlated with age, sex, blood cholesterol level and history of diabetes or hypertension. No positive correlation occurred between the arteriographic measures of disease and the cigarette smoking history. Thus, factors influencing the presence of disease may differ from those influencing its extent and severity.
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Jay G, Khoury G, Seth AK, Jay E. Construction of a general vector for efficient expression of mammalian proteins in bacteria: use of a synthetic ribosome binding site. Proc Natl Acad Sci U S A 1981; 78:5543-8. [PMID: 6272309 PMCID: PMC348782 DOI: 10.1073/pnas.78.9.5543] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
With the premise that mRNAs transcribed in Escherichia coli from cloned eukaryotic DNA inserts do not possess the necessary regulatory signals for recognition by prokaryotic ribosomes, we have constructed a general plasmid vector carrying a chemically synthesized prokaryotic ribosome binding site that will ensure the efficient expression of eukaryotic proteins in E. coli. In addition to the regulatory signals necessary for ribosome recognition, the synthetic segment contains, at one end, a Pst I cleavage site which will direct its insertion to pBR322 DNA and, at the other end, a HindIII site to facilitate attachment of the passenger eukaryotic gene. Using simian virus 40 (SV40) tumor (t) antigen as a model system, we have ligated the SV40 DNA fragment containing the entire t antigen gene in tandem with the synthetic ribosome binding site to pBR322 DNA at the Pst I site, which lies within the coding sequence of the beta-lactamase gene. Initiation of transcription at the beta-lactamase promoter would produce a chimeric mRNA with the synthetic ribosome binding signals and the SV40 sequence flanked by beta-lactamase coding sequences. Utilization of the synthetic regulatory signals for initiation of translation is demonstrated by the efficient synthesis, in bacterial transformants, of authentic SV40 t antigen. Excision of the entire SV40 insert by HindIII from those clones that have retained intact HindIII sites at the junction between the ribosome binding site and the SV40 sequence would allow insertion of other heterologous DNAs by using HindIII linkers. The efficient expression of any DNA insert would require that the entire coding sequence be contiguous and that its termini be randomized by treatment with exonuclease III and nuclease S1 to vary the distance between the translational initiation codon and the synthetic ribosome binding site.
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Seth AK, Jay E. A study of the efficiency and the problem of sulfonation of several condensing reagents and their mechanisms for the chemical synthesis of deoxyoligoribonucleotides. Nucleic Acids Res 1980; 8:5445-59. [PMID: 6894029 PMCID: PMC324313 DOI: 10.1093/nar/8.22.5445] [Citation(s) in RCA: 60] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The efficiencies and problems of sulfonation of several condensing reagents for deoxyoligoribonucleotide synthesis have been studied. While 2,4,6-triisopropylbenzenesulfonyl chloride (TPSC1) gave very low yield and slow rate of coupling, the new 1:3 mixture of TPSC1 and tetrazole afforded excellent yield and extremely fast rate of reaction with the lowest rate of sulfonation. The difference and advantages of this mixture over triisopropylbenzenesulfonyl tetrazole (TPSTe) and mesitylenesulfonyl tetrazole (MSTe) are discussed. Mechanisms for the coupling reactions with these condensing reagents to account for the difference in their rates and yields of coupling are discussed.
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171
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Jay E, Seth AK, Jay G. Specific binding of a chemically synthesized prokaryotic ribosome recognition site. Prospect for molecular cloning and expression of eukaryotic genes. J Biol Chem 1980; 255:3809-12. [PMID: 6989827] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
An icosadeoxyribonucleotide containing the several features found in prokaryotic mRNA ribosome binding sites has been synthesized. This sequence can stimulate the binding of initiator fMet-tRNAf to the ribosome to form a stable 71 S initiation complex identical with those induced by natural messengers. The binding of this synthetic ribosome binding site is absolutely dependent upon initiation factor IF3, and the bound fMet-tRNAf is sensitive to puromycin indicating the formation of a functional initiation complex. A heptadecadeoxyribonucleotide, identical with the icosanucleotide but lacking the terminal A-T-G codon, can also stimulate the stable binding of fMet-tRNAf to the ribosome, suggesting that the selection of the proper A-U-G initiation codon by fMet-tRNAf is subsequent to and a result of the recognition and binding of the fMet-tRNAf . 30 S ribosome complex to the initiation site. The prospect of ligating a similar synthetic ribosome binding site in front of a eukaryotic gene for cloning in an appropriate prokaryotic vector to assure the expresion of the protein is discussed.
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Rao NS, Seth AK, Murthy NS, Marwah SM. Some statistical deficiencies in medical research in India. Indian J Med Res 1977; 66:696-703. [PMID: 608737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
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Abstract
Kinetin (6-furfurylaminopurine) is generally considered to be relatively immobile within plants. Kinetin labeled with (14)C was applied to the stumps of decapitated bean plants, with or without simultaneous application of indoleacetic acid. Significantly greater amounts of kinetin moved downwards in the stem in the presence of added indoleacetic acid than in its absence.
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Abstract
The effects of auxin on the inhibition of lateral buds in decapitated bean plants are enhanced if kinetin is applied together with auxin. The uptake of (14)C-indoleacetic acid by the stumps of decapitated plants is increased in the presence of kinetin and leads to extensive transport of (14)C-indoleacetic acid in the stems. The increased bud inhibition resulting when auxin and kinetin are applied together may be due to greater amounts of auxin reaching the buds, but an alternative explanation is that metabolites are directed from the buds to the point of hormone application.
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