Biomedical subjects

C B Wilson

Publications and source records attributed to C B Wilson.

At least 145 records · Page 8Linked to original sources

PubMed1994

Age-related and gender-related occurrence of pituitary adenomas.

OBJECTIVE: To evaluate the various types of pituitary adenomas according to sex and age group. Few studies have attempted such an analysis, and most have focused on specific age groups, especially children. Recent data suggest that the frequency of different types of pituitary adenomas varies according to age and sex. DESIGN: A retrospective review of the records of 2230 patients who underwent surgery for a pituitary adenoma at the University of California, San Francisco (UCSF), between January 1969 and June 1993. METHODS: The distribution of tumours was analysed according to age at surgery, sex, and the clinical phenotype of the tumour. Age groups were defined as the decades of life. RESULTS: Prolactinomas were the most common tumours (39%), followed by endocrine-inactive adenomas, growth-hormone-releasing adenomas, and adrenocorticotrophic hormone-releasing adenomas causing Cushing's disease; ACTH-releasing adenomas causing Nelson's syndrome and thyrotrophin (TSH)-releasing adenomas were rare. The female-to-male ratio differed considerably between the various adenoma types and between age groups. Prolactinomas, ACTH-releasing adenomas, and TSH-releasing adenomas occurred mostly in females; endocrine-inactive and GH-releasing adenomas occurred mostly in males. In older age groups, all adenoma types, except for endocrine-inactive adenomas, tended to assume a more balanced gender distribution. Among patients with prolactinomas, endocrine-inactive, ACTH-releasing, and to a lesser extent GH-releasing adenomas, the greatest discrepancy in gender distribution seemed to coincide with the peak occurrence of each tumour type. The peak occurrence was from the second to the fifth decade of life for prolactinomas and from the fourth to the eighth decade for endocrine-inactive adenomas. GH-releasing, ACTH-releasing, and TSH-releasing adenomas were more evenly distributed throughout the adult life span. CONCLUSIONS: The frequency of pituitary adenomas varies greatly according to age and sex. The various adenoma types have their peak occurrence in distinctly different age groups and differ greatly in their female-to-male ratios. The female-to-male ratio for a given adenoma type varies greatly with age.

Adenoma↗

PubMed1994

An assembly domain of the Rous sarcoma virus Gag protein required late in budding.

The Gag protein of Rous sarcoma virus has the ability to direct particle assembly at the plasma membrane in the absence of all the other virus-encoded components. An extensive deletion analysis has revealed that very large regions of this protein can be deleted without impairing budding and has suggested that the essential functions map to three discrete regions. In the studies reported here, we establish the location of assembly domain 2 (AD2) within the proline-rich p2b sequence of this Gag protein. AD2 mutants lacking the p2b sequence were completely defective for particle release even though their Gag proteins were tightly associated with the membrane fraction and exhibited high levels of protease activity. Mutations that inactivate the viral protease did not restore budding to wild-type levels for these mutants, indicating that the defect is not due simply to a loss of protease regulation. AD2 mutants could be rescued into dense particles in genetic complementation assays, indicating that their defect is not due to a gross alteration of the overall conformation of the protein and that the assembly function is not needed on every Gag molecule in the population. Several mutants with amino acid substitutions in the p2b sequence were found to have an intermediate capacity for budding. Inactivation of the protease of these mutants stabilized the Gag polyprotein within the cells and allowed an increase in particle release; however, the rate of budding remained slow. We favor the idea that AD2 is a dynamic region of movement, perhaps serving as a molecular hinge to allow the particle to emerge from the surface of the cell during budding.

Amino Acid Sequence↗

PubMed1994

Radiation-induced telangiectasia in the brain simulates cryptic vascular malformations at MR imaging.

PURPOSE: To analyze the magnetic resonance (MR) imaging, clinical, and pathologic features of radiation-induced telangiectasia of the brain. MATERIALS AND METHODS: The clinical and radiation therapy records were reviewed of 20 patients who developed focal hypointense lesions on T2-weighted MR images obtained after radiation therapy of the central nervous system. Pathologic material was reviewed in six patients. RESULTS: Eleven patients had solitary lesions, and nine had multiple foci on MR images. Fourteen of the 20 patients were less than 20 years old. The appearance ranged from small hypointense foci to larger regions of acute hemorrhage. Hematomas occurred at the site of a previously identified focus of T2 shortening in five patients. Pathologic findings included ectatic thin-walled vessels surrounded by hemosiderin and gliosis, with minimal evidence of necrosis. CONCLUSION: Radiation-induced telangiectasia in the brain results in varying amounts of hemorrhage and, occasionally, parenchymal hematomas, and may appear similar to cryptic vascular malformations on T2-weighted MR images.

Adolescent↗

PubMed1994

Interleukin-1 alpha stimulates KC synthesis in rat mesangial cells: glucocorticoids inhibit KC induction by IL-1.

To assess the possible role of the production of chemokines by intrinsic glomerular cells in the generation of inflammation in glomerulonephritis, the chemokine, KC, was cloned from a rat macrophage cDNA library. Transfection of rat KC into COS-7 cells resulted in increased neutrophil chemotactic activity. The KC cDNA was expressed as a fusion protein in Escherichia coli for generation of an antibody. By using a riboprobe derived from the cDNA and the antibody, interleukin-1 (IL-1) was found to induce the expression of KC in rat mesangial cells. The induction of KC by IL-1 could be inhibited by dexamethasone (DEX). The protein synthesis inhibitor cycloheximide reversed the DEX-mediated inhibition, which suggested that new protein synthesis was necessary for the inhibitory effect. A nuclear runoff analysis indicated that DEX inhibited the transcription of KC induced by IL-1. The stability of KC mRNA was not decreased in the presence of DEX. Furthermore, immunoblots showed that DEX also inhibited KC expression at the level of translation. Together the inhibition of transcription and translation of the KC gene by DEX contribute to decreased KC expression in mesangial cells. The finding that mesangial cells express KC in response to proinflammatory cytokines, such as IL-1, points to a central role for the mesangial cell as a chemotactic source in glomerular inflammation.

Animals↗

PubMed1994

Expression of mRNA for natriuretic peptide receptor subtypes in bovine kidney.

The localization of mRNA for atrial natriuretic peptide (ANP) receptor subtypes (A, B, C) in the kidney was examined. Quantitative analysis of the ribonuclease protection assay showed that the numbers of type A receptor (ANPRA) mRNA were 6.9 x 10(7) in the glomeruli and 10.4 x 10(7) molecules/micrograms of total RNA in the inner medulla, and that of type C receptor (ANPRC) mRNA was 21.7 x 10(7) molecules/micrograms of total RNA in the glomeruli. The type B receptor (ANPRB) mRNA was present in smaller numbers (4.5-4.9 x 10(6) molecules/micrograms of total RNA) evenly throughout the kidney fractions. In situ hybridization demonstrated both ANPRA and ANPRC mRNA selectively in the glomerular epithelial cells and ANPRA mRNA in the collecting duct cells of the inner medulla. ANPRC was also localized on the foot processes of glomerular epithelial cells by immunohistochemistry using a specific antibody against the receptor. These results indicate that ANPRA is the major biologically active receptor for the ANP family of hormones in the kidney and is present selectively on the glomerular epithelial cells and inner medullary collecting duct cells. These cells are presumed to play a role in the regulation of glomerular filtration rate and sodium excretion induced by the family of ANP.

Animals↗

PubMed1994

Glomerular hemodynamics in cell-free and erythrocyte-perfused isolated rat kidney.

The cell-free isolated perfused kidney (IPK) is characterized by normal glomerular filtration rate (GFR) and very low filtration fraction (FF). Addition of erythrocytes to the perfusate (IEPK) increases FF while maintaining "normal" GFR levels. Micropuncture studies were performed in IPK and IEPK to establish the determinants of the glomerular ultrafiltration process responsible for low FF in IPK and to evaluate the impact of the addition of erythrocytes on these determinants. Nephron filtration rate was similar in IPK and IEPK (40 +/- 4 vs. 39 +/- 4 nl/min), whereas nephron perfusate flow was significantly higher in IPK (1,247 +/- 100 vs. 112 +/- 13 nl/min), leading to a superficial nephron FF of 3.4 +/- 0.2% in IPK and 36 +/- 2% in IEPK. Glomerular hydrostatic pressure (PG) and transcapillary hydrostatic pressure gradient (delta P) were 53 +/- 2 and 33 +/- 1 mmHg, respectively, in IPK and 51 +/- 3 and 34 +/- 2 mmHg in IEPK, all normal values. Glomerular arteriolar resistances were significantly lower in IPK than in IEPK, and the glomerular ultrafiltration coefficient (LpA) was significantly lower in IPK (0.053 +/- 0.010 vs. 0.100 +/- 0.020 nl.s-1.mmHg-1), but both values are within the normal in vivo range. These results demonstrate that low FF in IPK is not due to decreased delta P or LpA values but to the high renal perfusion rate required to maintain normal PG and delta P values. Addition of erythrocytes increases glomerular arteriolar resistances and restores glomerular hemodynamics to a pattern nearly identical to in vivo conditions.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1994

Interleukin-1 receptor antagonist ameliorates experimental anti-glomerular basement membrane antibody-associated glomerulonephritis.

The contribution of IL-1 to leukocyte infiltration in anti-glomerular basement membrane (GBM) antibody (Ab) glomerulonephritis (GN) was examined by the administration of a specific IL-1 receptor antagonist (IL-1ra). Lewis rats received anti-GBM Ab or normal rabbit serum and were treated with either 0.9% saline or 6 mg IL-1ra over a 24-h time period. Plasma IL-1ra concentration was 2,659 +/- 51 ng/ml 4 h after anti-GBM Ab and IL-1ra administration. PMN and monocyte/macrophage infiltration declined 39% (9.8 +/- 1.9 to 6.0 +/- 1.5 PMN/glomerulus, P < 0.001) and 29% (4.9 +/- 0.8 to 3.5 +/- 0.8 ED-1 cells/glomerulus, P = 0.002) with IL-1ra treatment at 4 h, respectively. Similarly, the number of glomerular cells staining for lymphocyte function-associated molecule-1 beta (CD18) declined 39% from 16.7 +/- 1.9 to 10.7 +/- 1.6 cells/glomerulus at 4 h (P = 0.0001). This was associated with a decrease in glomerular intracellular adhesion molecule-1 expression. The mean glomerular intracellular adhesion molecule-1 score in anti-GBM Ab GN rats treated with IL-1ra was less than that of rats administered anti-GBM Ab and 0.9% saline at 4 (2.0 +/- 0.2 vs 2.5 +/- 0.2, P < 0.05) and 24 (2.5 +/- 0.1 vs 3.1 +/- 0.2, P = 0.0001) h. These immunopathologic changes correlated with a 50% reduction in proteinuria from 147 +/- 34 to 75 +/- 25 mg/d (P < 0.002). Treatment with IL-1ra did not affect the steady state mRNA expression of either IL-1 beta or TNF alpha. An increase in the IL-1ra dose to 30 mg given within the initial 4 h provided no additional benefit. The decline in PMN and monocyte/macrophage infiltration of the glomerulus at 4 h was similar to that found in the initial study. Furthermore, the protective benefit of IL-1ra was abrogated by doubling the dose of the anti-GBM Ab GN, despite administering high dose IL-1ra (30 mg). In these studies, detectable IL-1ra was found in the serum of untreated anti-GBM Ab GN controls. These data suggest a positive yet limited role for IL-1ra in the therapeutic intervention of anti-GBM Ab GN.

Animals↗

PubMed1994

Protein C inhibitor is expressed in tubular cells of human kidney.

Protein C inhibitor (PCI) is a serpin that inhibits a number of proteases. PCI is found in urine and binds to kidney epithelial cells. To determine if kidney is a source of PCI, cDNA was produced from human kidney total RNA. Sequencing and restriction mapping showed identity between kidney and liver PCI cDNA sequences. Similar cDNAs were obtained from rhesus monkey kidney and liver RNAs. Conditioned medium from the rhesus monkey kidney cell line CCL7.1 was analyzed on immunoblots, showing a 57,000-D protein band that comigrated with human plasma PCI. Immunohistochemical staining and in situ hybridization of human kidney tissue sections showed that kidney PCI antigen and RNA were confined to tubular cells. The findings are consistent with the idea that PCI is synthesized and localized in kidney tissue where it may provide protease inhibitory activity and suggest that complexes of PCI with urokinase found in human urine may be produced locally in the kidney.

Base Sequence↗

PubMed1994

Changes in the immunophenotype of recurrent pituitary adenomas.

Only two cases have been reported of a pituitary adenoma that changed phenotype between its initial resection and recurrence. To determine the frequency of such cases among our patients, we examined the clinical course of these tumors and characterized any patterns. We reviewed the charts of 1023 patients with pituitary adenomas who underwent surgery between 1984 and 1992 at the University of California at San Francisco. Of the 65 patients (6.4%) who had operations for or clinical evidence of tumor recurrence, five (7.7%) had tumors that changed phenotype. The female-to-male ratio was 4:1, and age at the onset of symptoms was 33.2 +/- 15.3 years (mean +/- standard deviation). Changes occurred in hormone production and hormone release after 6.4 +/- 3.4 years. At some point, all five tumors were invasive and four were macroadenomas. Two patients had more than one operation for tumor recurrence; three had silent or symptomatic pituitary apoplexy; and three had undergone sellar irradiation before the changes in phenotype occurred. The behavior of these tumors therefore seems to be aggressive. We do not yet know whether phenotypic changes in pituitary adenomas have any treatment implications. Therefore, we advocate the complete immunostaining of primary and recurrent pituitary adenomas so that additional data about their clinical course can be collected.

Adenoma↗

PubMed1994

Water and protein permeability is regulated by the glomerular epithelial slit diaphragm.

The glomerular barriers to water and macromolecular movement were examined 2 and 24 h after the administration of a monoclonal antibody (mAb) specific to an antigen located on the epithelial slit diaphragm and the external aspect of the glomerular basement membrane. By micropuncture techniques 2 h after mAb administration, single-nephron GFR (SNGFR) and plasma flow were unchanged but the glomerular capillary hydrostatic pressure gradient and glomerular capillary hydrostatic pressure were increased and the glomerular ultrafiltration coefficient (LpA) decreased to values that were 50% of the normal control. There was no increase in urinary protein excretion at 2 h. However, at 24 h after mAb, nephron plasma flow (SNPF) and SNGFR increased and the glomerular ultrafiltration coefficient returned to values indistinguishable from the normal control. At 24 h, there was a marked increase in protein excretion. The administration of meclofenamate decreased values for SNGFR and SNPF to normal. Immunoglobulin G was exclusively bound to glomerular capillary walls in a linear or continuous fashion at 2 h, but in a discontinuous, granular pattern at 24 h. These studies suggest that after mAb, important limiting glomerular barriers for hydraulic conductivity and protein excretion reside on the epithelial aspect of the glomerular capillary basement membrane, specifically at the level of the slit diaphragm. Studies also suggest that alterations in glomerular capillary hydraulic conductivity can be effectively separated from increases in macromolecular permeability.

Animals↗

PubMed1994

Postoperative irradiation for subtotally resected meningiomas. A retrospective analysis of 140 patients treated from 1967 to 1990.

The authors retrospectively analyzed 140 patients treated at the University of California, San Francisco, from 1967 to 1990 to evaluate the results of radiation therapy (median 5400 cGy) given as an adjuvant to subtotal resection of intracranial meningioma. Of the 140 meningiomas, 117 were benign and 23 were malignant. The median follow-up period was 40 months. The overall survival rate at 5 years was 85% for the benign and 58% for the malignant tumor groups (p = 0.02); the 5-year progression-free survival rates were 89% and 48%, respectively (p = 0.001). For patients with benign meningioma, the 10-year overall and progression-free survival rates were 77%. An improved progression-free survival rate in that group was not related to tumor size but was associated with a younger age (p = 0.01) and treatment after 1980 with innovative technologies (p = 0.002); none of those variables affected the progression-free survival rate in the patients with malignant meningioma. Increased progression-free survival in the benign tumor group was also significantly associated with increasing the minimum radiation dose (p = 0.04). The 5-year progression-free survival rate for patients with benign meningioma treated after 1980 (when computerized tomography or magnetic resonance imaging was used for planning therapy) was 98%, as compared with 77% for patients treated before 1980 (p = 0.002). There were no second central nervous system tumors. Morbidity (3.6%) included sudden blindness or cerebral necrosis and death. When total resection of benign meningioma is not feasible, subtotal resection combined with precise treatment planning techniques and adjuvant radiation therapy can achieve results comparable to those of total resection.

Adolescent↗

PubMed1994

Development of acquired arteriovenous fistulas in rats due to venous hypertension.

Dural sinus thrombosis has been hypothesized as a possible cause of dural arteriovenous fistulas (AVF's). The pathogenesis and evolution from thrombosis to actual development of an AVF are still unknown. To study dural fistula formation, a surgically induced venous hypertension model in rats was created by producing an arteriovenous shunt between the carotid artery and the external jugular vein. The external jugular vein beyond the anastomosis was ligated 2 to 3 months after surgery and angiography was performed to identify any new acquired AVF's. Forty-six male Sprague-Dawley rats, each weighing approximately 300 gm, were used for this study. In Group I, 22 rats underwent a common carotid artery anastomosis to the external jugular vein, which is the largest draining vein from the transverse sinus via the posterior facial vein, followed by proximal external jugular vein ligation. In Group II, 13 rats underwent the same surgical procedure, followed by contralateral posterior facial vein occlusion. Group III served as the control group, in which 11 rats underwent only unilateral external jugular vein occlusion with or without contralateral posterior facial vein occlusion. The shunts in Groups I and II were ligated at 2 to 3 months following surgery, and transfemoral angiography was performed immediately before and after occlusion. New acquired AVF's had developed in three rats (13.6%) in Group I, three rats (23.1%) in Group II, and no rats (0%) in Group III. One of these newly formed fistulas was located at the dural sinus, analogous to the human dural AVF. The other five were located in the subcutaneous tissue, including the face and neck. The dural AVF in the rat was present on follow-up angiography at 1 week after the bypass occlusion. It is concluded that chronic venous hypertension of 2 to 3 months' duration, without associated venous or sinus thrombosis, can induce new AVF's affecting the dural sinuses or the subcutaneous tissue.

Animals↗

PubMed1994

Meningiomas: genetics, malignancy, and the role of radiation in induction and treatment. The Richard C. Schneider Lecture.

The author reviews the molecular genetics, pathology, and cell kinetics of meningiomas and the role that regional multiplicity in the dura mater may play in their recurrence. Malignant and radiation-induced meningiomas are discussed, with summaries of series of 60 patients with frankly malignant lesions treated over a period of 22 years at the University of California, San Francisco, and of 10 patients with meningiomas induced by high-dose radiation therapy. Reviewing a 23-year series of 140 patients with subtotally removed meningiomas who were treated post-operatively with radiation, the author recommends that, with meticulous technique, irradiation is effective in preventing the regrowth of subtotally removed benign meningiomas and of all malignant meningiomas. Adoption of both the microscopical cytological grading system proposed by Jääskeläinen's group in Helsinki and the classification of operations proposed by Donald Simpson is also recommended. Wide removal of dura adjacent to meningioma reduces the risk of recurrence, and determination of the bromodeoxyuridine labeling index provides a valid basis for planning treatment and follow-up evaluations. Increased awareness is necessary for early recognition of radiation-induced meningiomas in patients at risk for developing such tumors. For meningiomas in such sites as the parasellar region and the posterior fossa, conservative removal of tumor followed by irradiation is advocated in preference to a radical operation that may cause neurological injury without being curative.

Cell Cycle↗

PubMed1994

Cushing's disease. Therapy of pituitary adenomas.

Treatment of Cushing's disease has evolved over the past 20 years from the era of bilateral adrenalectomy to the current era of pituitary microsurgery. Therapy directed to the pituitary gland is currently the first approach in Cushing's disease and transphenoidal exploration of the sellar contents is the procedure of choice. Tumor localization and pituitary surgery are reviewed. Pituitary radiotherapy, pharmacologic inhibition of ACTH secretion, and Nelson's syndrome are also discussed.

Adenoma, Basophil↗

PubMed1994

Renal functional reserve in experimental chronic glomerulonephritis.

Loss of renal functional reserve, that is, absence of the glomerular vasodilatory response to amino-acid infusion, has been interpreted as equivalent to glomerular hyperperfusion/hypertension, and therefore proposed as a marker of high risk for progressive glomerular sclerosis. To substantiate the validity of this hypothesis we evaluated the renal response to glycine and the extent of glomerular damage 10-12 weeks after induction of anti-glomerular basement membrane glomerulonephritis with or without superimposed clip hypertension. Untreated rats and rats chronically treated with quinapril, a converting-enzyme inhibitor, were studied. In untreated groups, loss of renal functional reserve was demonstrated since GFR, single-nephron GFR (SNGFR) and plasma flow (SNPF) did not increase during glycine infusion. The absence of renal reserve was associated with glomerular hyperfusion/hypertension, and development of proteinuria and glomerulosclerosis. Quinapril reduced proteinuria and diffuse sclerosis in anti-glomerular basement membrane GN, and decreased blood pressure and segmental glomerulosclerosis in antiglomerular basement membrane GN with superimposed clip hypertension. Both treated groups demonstrated a restoration of renal functional reserve, as depicted by increases in GFR, SNGFR, and SNPF after glycine, despite persistence of glomerular hyperperfusion/hypertension. These data demonstrate that renal functional reserve testing, although it does not detect glomerular hyperperfusion/hypertension, can provide information on the progression of glomerular damage.

Angiotensin-Converting Enzyme Inhibitors↗

PubMed1994

Cytokine expression, upregulation of intercellular adhesion molecule-1, and leukocyte infiltration in experimental tubulointerstitial nephritis.

BACKGROUND: Cytokines are intercellular polypeptide messengers that mediate immune and inflammatory responses. The temporal profile of interleukin-1 beta (IL-1 beta), IL-6, tumor necrosis factor alpha (TNF-alpha), and monocyte chemotactic protein 1 (MCP-1) expression was examined in anti-tubular basement membrane (TBM) antibody-associated tubulointerstitial nephritis (TIN). EXPERIMENTAL DESIGN: TIN was induced by immunization of Brown Norway rats with bovine cortical TBM, whereas control rats received ovalbumin. Whole kidney RNA was assessed with the RNase protection assay 3, 7, 8, 9, 10, 12, and 14 days after immunization. Cytokine mRNA expression was correlated with TNF-alpha bioactivity, renal intercellular adhesion molecule-1 expression, and CD18-positive leukocyte infiltration by immunohistochemistry. RESULTS: Increased IL-1 beta, TNF-alpha, and MCP-1 mRNA relative to glyceraldehyde-3-phosphate dehydrogenase appeared on day 7 when TIN involved 10 to 40% of the cortex, and peaked rapidly on day 8 when there was 60 to 80% cortical involvement (at which time 75 to 80% of the infiltrating cells were neutrophils). The increase in TNF-alpha mRNA correlated with increased bioactivity. The influx of mononuclear cells on day 8 was preceded by the expression of MCP-1 mRNA. The infiltrating leukocytes expressed the leukocyte beta 2-integrin (CD18) and were found in areas with increased intercellular adhesion molecule-1 expression. The mRNAs for IL-1 beta, TNF-alpha, and MCP-1 were undetectable by day 10 (at which time 95% of the infiltrating cells were mononuclear). An increase in IL-1 receptor antagonist mRNA paralleled those of IL-1 beta. The expression of IL-6 mRNA was similar to that for IL-1, except that it disappeared by day 9. CONCLUSIONS: There is a temporal association in the expression of IL-1 beta, TNF alpha, MCP-1, and IL-6 with the upregulation of intercellular adhesion molecule-1 and leukocyte infiltration within the tubulointerstitium in anti-TBM antibody-associated TIN. The narrow window of time through which these cytokines are expressed and the coincidence of their peak expression on day 8 suggest complex cytokine interactions in the pathogenesis of anti-TBM antibody TIN.

Animals↗

PubMed1993

Two essential regulatory elements in the human interferon gamma promoter confer activation specific expression in T cells.

Like interleukin 2 (IL-2), interferon gamma (IFN-gamma) is an early response gene in T cells and both are prototypical T helper cell type 1 (Th-1) lymphokines. Yet IL-2 and IFN-gamma production are independently regulated, as demonstrated by their differential expression in certain T cell subsets, suggesting that the regulatory elements in these two genes must differ. To explore this possibility, the 5' flank of the human IFN-gamma gene was analyzed. Expression of IFN-gamma promoter-driven beta-galactosidase reporter constructs containing 538 bp of 5' flank was similar to that by constructs driven by the IL-2 promoter in activated Jurkat T cells; expression nearly as great was observed with the construct containing only 108 bp of IFN-gamma 5' flank. These IFN-gamma promoter constructs faithfully mirrored expression of the endogenous gene, in that expression required activation both with ionomycin and PMA, was inhibited by cyclosporin A, and was not observed in U937 or THP-1 cells. The region between -108 and -40 bp in the IFN-gamma promoter was required for promoter function and contained two elements that are conserved across species. Deletion of 10 bp within either element reduced promoter function by 70%, whereas deletions in nonconserved portions of this region had little effect on promoter function. The distal conserved element (-96 to -80 bp) contained a consensus GATA motif and a potential regulatory motif found in the promoter regions of the GM-CSF and macrophage inflammatory protein (MIP) genes. Factors binding to this element, including GATA-3, were found in Jurkat nuclear extracts by electromobility shift assays and two of the three complexes observed were altered in response to activation. One or both of these motifs are present in the 5' flank of multiple, other lymphokine genes, including IL-3, IL-4, IL-5, and GM-CSF, but neither is present in the promoter of the IL-2 gene. The proximal conserved element (-73 to -48 bp) shares homology with the NFIL-2A element in the IL-2 promoter; these elements compete for binding of factors in Jurkat nuclear extracts, although the NFIL-2A element but not the IFN-gamma element binds Oct-1. Factors binding to this element in the IFN-gamma gene were present in extracts from resting and activated Jurkat T cells. However, by in vivo footprinting of intact cells, this element was protected from methylation only with activation.(ABSTRACT TRUNCATED AT 400 WORDS)

Base Sequence↗

PubMed1993

Cloning a novel form of rat PDGF A-chain with a unique 5'-UT: regulation during development and in glomerulonephritis.

An unique form of rat platelet-derived growth factor A-chain (PDGF A-chain), with a novel 5' UT region, was cloned from a rat macrophage cDNA library and expressed. In the 5' UT, the homology of the 79 bp sequence adjacent to the ATG codon between rat and human was 92%; however, the homology of the remainder in the 5' UT was less than 30%. RNase mapping indicated this form was differentially expressed during development and immune glomerular injury, and that it probably arose from alternative splicing. We propose that the variant mRNAs reflect different levels of the control of PDGF A-chain expression.

Aging↗