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1.
Infect Dis Now ; 52(8): 441-446, 2022 Nov.
Article in English | MEDLINE | ID: mdl-36030041

ABSTRACT

BACKGROUND: By analysing the largest collection of Corynebacterium glucuronolyticum (C. glucuronolyticum) isolates from a single centre thus far, we aimed to appraise a potential causal link between an infrequently isolated species and the urethritis syndrome in men. METHODS: A total of 1055 Caucasian male individuals with or without urethritis syndrome were included in this single-centre case-control study. Group-wise comparisons were pursued by analysing sociodemographic, behavioural and microbiological specificities between the two groups. C. glucuronolyticum isolates from urethral specimens were identified using the analytical profile index biotyping system (API Coryne) and additionally confirmed by MALDI-TOF mass-spectrometry, with subsequent determination of their antimicrobial sensitivity profiles. Statistical significance was set at p < 0.05 (two-tailed). RESULTS: C. glucuronolyticum was isolated in 5.08% of study participants with urethritis syndrome and 3.60% of those without it (p = 0.303). In the urethritis group, the species was more frequently found as a sole isolate (p = 0.041) and after prior infection with Chlamydia trachomatis (p = 0.025). The most frequent presentation of urethritis included a clear discharge in small or moderate amounts, without any pathognomonic findings. The resistance rates were 62.22% for clindamycin, 42.22% for tetracycline and 26.67% for ciprofloxacin. CONCLUSIONS: Our study provides major insights on the relevance of urethral C. glucuronolyticum in non-gonococcal urethritis, with significant implications for further aetiological research and management approaches.


Subject(s)
Urethritis , Humans , Male , Urethritis/drug therapy , Urethritis/epidemiology , Urethritis/etiology , Case-Control Studies , Corynebacterium , Chlamydia trachomatis , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/therapeutic use
3.
Andrology ; 6(1): 223-229, 2018 Jan.
Article in English | MEDLINE | ID: mdl-29216684

ABSTRACT

Corynebacterium glucuronolyticum (C. glucuronolyticum) is a rare isolate that is only recently being acknowledged as a potential urogenital pathogen. The bibliographical references on this bacterial species are scarce, and its influence on all semen parameters was hitherto unknown - therefore, the aim of this study was to evaluate its effects on a range of sperm quality parameters. A prospective approach to compare semen parameters before and after treatment was used in this study. C. glucuronolyticum in semen specimens was identified using analytical profile index biotyping system (API Coryne) and additionally confirmed by matrix-assisted laser desorption/ionization time-of-flight mass-spectrometry (MALDI-TOF MS), with the determination of antimicrobial susceptibility by Kirby-Bauer method. Semen analysis was performed according to the criteria from the World Health Organization (with the use of Tygerberg method of sperm morphology categorization). Very strict inclusion criteria for participants also included detailed medical history and urological evaluation. From a total of 2169 screened semen specimens, the inclusion rate for participants with C. glucuronolyticum that satisfied all the criteria was 1.01%. Antibiogram-guided treatment of the infection with ensuing microbiological clearance has shown that the resolution of the infection correlates with statistically significant improvement in the vitality of spermatozoa, but also with a lower number of neck and mid-piece defects. Parameters such as sperm count, motility and normal morphology were not affected. In addition, susceptibility testing revealed a trend towards ciprofloxacin resistance, which is something that should be considered when selecting an optimal treatment approach. Albeit it is rarely encountered as a monoisolate in significant quantities, C. glucuronolyticum may negatively influence certain sperm parameters; therefore, it has to be taken into account in the microbiological analysis of urogenital samples.


Subject(s)
Corynebacterium Infections/complications , Corynebacterium Infections/epidemiology , Semen/microbiology , Adult , Cohort Studies , Corynebacterium glutamicum , Humans , Male , Middle Aged , Prospective Studies , Sperm Count , Sperm Motility , Young Adult
4.
Acta Med Croatica ; 70 Suppl 1: 25-30, 2016.
Article in Croatian | MEDLINE | ID: mdl-29087667

ABSTRACT

Practical experience and numerous studies have shown that, after finishing their studies nursing graduates are not sure in their independent assessment and treatment of wounds. It appears that nursing education lacks narrowly specialized educational content in this area, practical skills and connection between graduates and experts who follow the standards and guidelines in the area of wound healing. The aim of this study was to assess the knowledge through tests and attitudes of nurses/nursing graduates on the condition of the skin and damage treatment. In addition, the study was also aimed at learning about possible guidelines for the future content of the nursing curriculum studies in Croatia. The study was conducted on a sample of 71 students (six (8.5%) male and 65 (91.5%) female of Nursing Studies at University North. The subjects voluntarily and anonymously completed the survey electronically. A semi-structured standardized questionnaire was used, "Knowledge test about the basis of pressure ulcers in geriatric patients", designed by Dr Andrija Stampar Department of Health Gerontology, Reference Center for Health Care of the Elderly of the Ministry of Health of the Republic of Croatia. The test administered to the sample of students of nursing, mostly aged 18-25 (64.8%) showed correct answers to 12 questions asked, in a range of 17.9% to 100% (median 60.6%, SD 24.1, Q1 53.8%, Q3 81%). Answers to question 13 (daily work with patients) revealed that 39.4% of students knew and often used modern approach to the prevention and treatment of pressure ulcers; the same percentage of students rarely used modern method of prevention and treatment of pressure ulcers, 26.8% were not familiar with the issue, while 2.8% were not interested in it. As for question 14 (given the existing contents on the treatment of pressure ulcers in the educational program for students of nursing), 47.9% of study subjects believed they needed more practical skills in treating pressure ulcers, 45.1% considered it necessary to introduce more contents on the treatment of pressure ulcers in regular courses, while 8.5% believed it was not necessary to introduce additional contents because there was enough knowledge on wound treatment. The results indicated that there was a relatively satisfactory partial knowledge to assess skin condition, prevention measures and treatment of pressure ulcers in the elderly, but also that more practical skills were needed in the treatment and modern dressing application, which can be considered as guidelines for future educational contents in the nursing studies. Based on the simple and standardized survey in a relatively broad sample of students of Nursing Studies at University North, student knowledge on the prevention and treatment of pressure ulcers with modern methods can be well assessed. Scarce practical knowledge in the field of modern pressure ulcer treatment, the lack of professional literature revision in terms of modern guidelines and theories, as well as poor collaboration of scientific educational and health institutions are the key problems of insufficient knowledge of nursing graduates in daily work of treating chronic wounds. Student insecurity related to prevention and therapy in modern treatment of pressure ulcers show a possible direction for future educational contents of nursing studies. Additional similar studies are warranted in order to get a more detailed insight into assessment of practical and theoretical knowledge of graduates about modern care of patients with chronic wounds.


Subject(s)
Education, Nursing, Graduate , Educational Measurement/methods , Pressure Ulcer , Skin Care , Croatia , Education, Nursing, Graduate/methods , Education, Nursing, Graduate/standards , Health Knowledge, Attitudes, Practice , Humans , Needs Assessment , Pressure Ulcer/nursing , Pressure Ulcer/prevention & control , Skin Care/methods , Skin Care/standards , Surveys and Questionnaires
5.
Ginekol Pol ; 72(12): 1037-41, 2001 Dec.
Article in Polish | MEDLINE | ID: mdl-11883205

ABSTRACT

RATIONALE: Flood disasters destroy environment of many people by causing physical as well as psychological harm. This may affect procreational behavior of the victims. DESIGN: This study examines reproductive behavior (number of live births) among the survivors from the flood disaster in Klodzko Region which took place in July 1997. The observation period was three years (1998-2000). MATERIALS AND METHODS: The harmed population consisted of 3986 subjects. The population from Klodzko Region which was exposed to flood disaster in 1997 consisted of 107,032 people. Among the injured population there were 1037 women in reproductive age. This population was studied. RESULTS: The results show significantly higher number of live births per 1000 and birth-rate in studied women as compared to the total population of a district. Psychological background of an observed phenomenon was discussed.


Subject(s)
Adaptation, Psychological , Delivery, Obstetric/psychology , Disasters , Postpartum Period/psychology , Sexual Behavior/psychology , Adult , Chi-Square Distribution , Female , Humans , Mothers/psychology , Multivariate Analysis , Poland , Pregnancy , Surveys and Questionnaires
6.
Ginekol Pol ; 71(4): 258-62, 2000 Apr.
Article in Polish | MEDLINE | ID: mdl-10860255

ABSTRACT

OBJECTIVES: The clinical analysis of deliveries ended by forceps over the period of ten years. DESIGN: Review of perinatal outcome and indications to use outlet and low forceps or midforceps. MATERIALS AND METHODS: Author analysed 137 forceps deliveries in comparison to control group of 250 normal, vaginal labours. Obstetrical history, indications to use vaginal operation, duration of labour, hospitalisation time, newborns state in Apgar score or arterial cord pH, PaO2, and fetal or maternal injures were statistically analysed. The American College of Obstetricians and Gynecologists (ACOG) 1988 forceps classification be adopted for deliveries. Using outlet, low forceps and midforceps concerned with vaginal operation. RESULTS: The common indications to use outlet or low forceps were prolonged second stage of labour. The most frequent indication for the midforceps was a risk of fetal asphyxia and neonatal hypoxia. A major fetal injury occurred in midforceps, particularly with fetal head rotations. Furthermore, midforceps delivery increased incidence of maternal perineal trauma. The outlet or low forceps was safe for fetal outcome and trauma of the birth canal in comparison to normal vaginal delivery. CONCLUSIONS: The prophylactic use of outlet or low forceps has beneficial impact on the neonate because it shortens second stage of labour and decreased the incidence of neonatal hypoxia. The midforceps delivery increased a perinatal disorders and using cesarean section are better for child and mother.


Subject(s)
Pregnancy Complications , Surgical Instruments , Asphyxia Neonatorum/diagnosis , Female , Humans , Infant, Newborn , Pregnancy , Pregnancy Outcome
7.
Ginekol Pol ; 70(5): 378-82, 1999 May.
Article in Polish | MEDLINE | ID: mdl-10462986

ABSTRACT

OBJECTIVES: A natural disaster has been defined as a disruption of human ecology that exceeds the capacity of the community to function normally. DESIGN: After the flood disaster in Klodzko Region, July 1997, the major problem in female adolescents was observed: secondary amenorrhea. MATERIALS AND METHODS: 17 female adolescents, aged 13-18, which injured from the flood disaster with secondary amenorrhea were investigated. A control random group consists of 17 girls diagnosed before oral contraception. Diagnostic work-up includes history, physical and psychological examinations, hormonal profiles, transvaginal ultrasonography, color Doppler analysis of utero-ovarian arterial blood flow. RESULTS: FSH, LH, E2 plasma levels and LH/FSH ratio were significantly lower in the amenorrheic group compared to normal girls. Prolactin serum levels after metoclopramid administration were significantly higher in the amenorrheic group. Lower impedance to blood flow in the intraovarian arteries have been shown. Psychosomatic disorders related to hypothalamic amenorrhoea were diagnosed. CONCLUSIONS: Psychosocial stress observed during the flood disaster caused hypogonadotropic hypogonadism amenorrhoea in the female adolescents.


Subject(s)
Amenorrhea/etiology , Disasters , Stress Disorders, Post-Traumatic/psychology , Adolescent , Body Mass Index , Catchment Area, Health , Female , Humans , Poland , Random Allocation , Retrospective Studies , Seasons , Time Factors
8.
Ginekol Pol ; 69(5): 358-62, 1998 May.
Article in Polish | MEDLINE | ID: mdl-9695343

ABSTRACT

Internal illiac and ovarian artery ligation was performed in 7 patients as a life saving measure (group I) and in 12 patients as a prophylactic procedure (group II) in 116 pelvic operations for gynaecological malignancy. The author presents own surgical technique for internal iliac and ovarian arteries ligation. The purpose of analysis was to identify a surgical complications after the ligation in the study groups. Surgical complications in the group of prophylactic ligation were statistically significant low. It is advisable to adopt this procedure as a routine in all difficult pelvic operations, particularly radical operations for gynaecological malignancy.


Subject(s)
Endometrial Neoplasms/surgery , Iliac Artery/surgery , Ovarian Neoplasms/surgery , Ovary/blood supply , Ovary/surgery , Sarcoma/surgery , Uterine Cervical Neoplasms/surgery , Adult , Aged , Female , Humans , Ligation , Middle Aged , Retrospective Studies
9.
Ginekol Pol ; 69(12): 866-70, 1998 Dec.
Article in Polish | MEDLINE | ID: mdl-10224743

ABSTRACT

OBJECTIVES: A natural disaster has been defined as a disruption of human ecology that exceeds the capacity of the community to function normally. Little is known about the influence of flood disaster on reproductive outcomes. DESIGN: This study reviews perinatal medical problems in pregnant women during the flood disaster from Klodzko Region in July 1997. MATERIALS AND METHODS: 47 pregnant women were investigated which injured from the flood disaster. We observed a psychosocial stress in this women. A control random group consists of 100 pregnant women in 1996. RESULTS: Reproductive outcomes include pregnancy loss in 55.3% and other severe disorders: premature delivery, missed abortion, birth asphyxia, premature rupture of membranes, intrauterine growth retardation. CONCLUSIONS: Psychosocial stress observed during the flood disaster cause many perinatal complications and pregnancy loss. Intensive perinatal medical care must usually be provided from outside the disaster area.


Subject(s)
Delivery, Obstetric/psychology , Disasters , Postpartum Period/psychology , Pregnancy Complications/psychology , Stress Disorders, Post-Traumatic/psychology , Adolescent , Adult , Female , Humans , Middle Aged , Poland , Pregnancy , Random Allocation
10.
Endocrine ; 7(1): 107-9, 1997 Aug.
Article in English | MEDLINE | ID: mdl-9449044

ABSTRACT

The loss or functional inactivation of tumor suppressor genes appears to be one of the most fundamental genetic mechanisms of tumorigenesis, and rational insights into the signaling pathways of tumor suppressor genes have emerged as a successful strategy of identifying novel drug discovery targets downstream of the tumor suppressor protein itself. Elucidation of novel pathways downstream of p53 have established a link between this important tumor suppressor gene and the insulin-like growth factor-1 receptor (IGF-1r), either via direct regulation of IGF-1 receptor levels, or modulation of IGFs via transactivation of the insulin-like growth factor-binding protein 3 (IGF-BP3) gene. Binding of IGF-BP3 to IGFs inhibits both their mitogenic and cell survival functions, highlighting a novel pathway whereby p53 may regulate apoptosis in tumor cells.


Subject(s)
Apoptosis/physiology , Genes, p53/physiology , Receptor, IGF Type 1/physiology , Animals , Apoptosis/drug effects , Apoptosis/genetics , Genes, p53/genetics , Humans , Insulin-Like Growth Factor Binding Protein 3/metabolism , Insulin-Like Growth Factor Binding Protein 3/pharmacology , Insulin-Like Growth Factor Binding Protein 3/physiology , Receptor, IGF Type 1/genetics
11.
Science ; 261(5128): 1551-7, 1993 Sep 17.
Article in English | MEDLINE | ID: mdl-8372350

ABSTRACT

In budding yeast genes that encode G1 cyclins and proteins involved in DNA synthesis are transcriptionally activated in late G1. A transcription factor, called SBF, is composed of Swi4 and Swi6 proteins and activates transcription of G1 cyclin genes. A different, but related, complex called MBF binds to MCB elements (Mlu I cell cycle box) found in the promoter of most DNA synthesis genes. MBF contains Swi6 and a 120-kilodalton protein (p120). MBF was purified and the gene encoding p120 (termed MBP1) was cloned. A deletion of MBP1 was not lethal but led to deregulated expression of DNA synthesis genes, indicating a direct regulatory role for MBF in MCB-driven transcription. Mbp1 is related to Swi4. Strains deleted for both MBP1 and SWI4 were inviable, demonstrating that transcriptional activation by MBF and SBF has an important role in the transition from G1 to S phase.


Subject(s)
Fungal Proteins/genetics , G1 Phase , S Phase , Saccharomyces cerevisiae Proteins , Saccharomyces cerevisiae/genetics , Transcription Factors/genetics , Amino Acid Sequence , Base Sequence , CDC28 Protein Kinase, S cerevisiae/genetics , CDC28 Protein Kinase, S cerevisiae/metabolism , Cloning, Molecular , Cyclins/genetics , DNA, Fungal/biosynthesis , DNA-Binding Proteins , Fungal Proteins/chemistry , Fungal Proteins/metabolism , Gene Expression Regulation, Fungal , Genes, Fungal , Molecular Sequence Data , Mutation , Promoter Regions, Genetic , Saccharomyces cerevisiae/cytology , Sequence Alignment , Transcription Factors/chemistry , Transcription Factors/metabolism
12.
Wiad Lek ; 45(9-10): 376-80, 1992 May.
Article in Polish | MEDLINE | ID: mdl-1441548

ABSTRACT

Human prolactin (hPRL) is a hormone produced by the lactotropic cells of the hypophysis and by the endometrium converted to decidua in pregnancy. Prolactin of decidual origin is identical with the pituitary hormone. Decidual prolactin is released mainly by the extraplacental fetal membranes. Prolactin production was found also in the endometrium in late secretory phase of normal menstrual cycle. It was noted that hPRL production by the decidua in various periods of pregnancy is closely correlated with hPRL concentration in the amniotic fluid. Peak hPRL release into the amniotic fluid is in the 24th week of pregnancy. The most important biological function of decidual prolactin is its effect on water and electrolyte transport for the needs of the fetus, and this transport takes place mainly across the fetal membranes. Moreover, it was found that prolactin affects the synthesis of fetal surfactant, influences calcium absorption in the fetal intestine. Calcium and phosphorus are obtained by the fetus from the amniotic fluid. Many authors suggest that decidual prolactin has a role in the process of implantation and early development of the blastocyst.


Subject(s)
Decidua/metabolism , Prolactin/physiology , Amniotic Fluid/metabolism , Biological Transport/physiology , Electrolytes/metabolism , Embryo Implantation/physiology , Female , Fetus/physiology , Humans , Pregnancy , Prolactin/metabolism , Water-Electrolyte Balance/physiology
13.
Oncogene ; 6(8): 1325-33, 1991 Aug.
Article in English | MEDLINE | ID: mdl-1909428

ABSTRACT

To elucidate the mechanisms involved in the transformation by fos we have initiated a study pertaining to the identification of molecular functions of Fos protein that are crucial for transformation. We have previously reported that the presence of an intact leucine zipper in Fos is an absolute requirement for the induction of transformation, but that the autorepression function of Fos is dispensable. We now show that Fos protein also needs an intact DNA (TRE)-binding site to be able to transform. Amino acid substitutions in this domain of Fos which impair DNA binding also destroy the transforming potential of Fos, suggesting that the interaction of Fos-Jun complexes with TREs may be a crucial part of Fos-induced transformation. This hypothesis is further strengthened by our observation that Fos and Jun can cooperate in the induction of transformation. We show that a Fos protein which contains a Jun leucine zipper and is thus capable of dimerization is still dependent on the presence of exogenous Jun to induce transformation. The critical positions in the Fos DNA-binding site include those which the 'scissors grip' model predicts to be crucial, although the DNA-binding site in Fos seems to extend beyond the basic region into an adjacent cluster of acidic amino acids.


Subject(s)
DNA/genetics , Mutagenesis, Site-Directed/genetics , Proto-Oncogene Proteins/genetics , Transformation, Genetic , Amino Acid Sequence , Base Sequence , DNA-Binding Proteins/genetics , Leucine Zippers/genetics , Molecular Sequence Data , Proto-Oncogene Proteins c-fos , Proto-Oncogene Proteins c-jun , Transcription Factors/genetics
14.
New Biol ; 3(7): 671-7, 1991 Jul.
Article in English | MEDLINE | ID: mdl-1751449

ABSTRACT

We show that trans-activation by v-Fos requires several functionally separable regions, including the leucine repeat, the basic DNA-binding region, a directly adjacent acidic cluster, and additional flanking sequences. Structural alterations in the flanking regions are in part responsible for the greater trans-activating potential of the fos gene product of the Finkel-Biskis-Reilly mouse osteosarcoma virus, FBR-MuSV. A point mutation in the acidic cluster, which is known to activate the immortalizing potential of Fos, leads to a significant increase in trans-activation. However, comparison of the trans-activating and transforming properties of mutant Fos proteins suggests that functions other than trans-activation are involved in the induction of transformation.


Subject(s)
Cell Transformation, Neoplastic/genetics , Oncogene Proteins v-fos/physiology , Transcription, Genetic/physiology , Transcriptional Activation/physiology , Cells, Cultured , Chloramphenicol O-Acetyltransferase/biosynthesis , Chromosome Mapping , DNA/metabolism , Electrophoresis, Polyacrylamide Gel , Gene Expression Regulation, Neoplastic , HeLa Cells , Humans , In Vitro Techniques , Oncogene Proteins v-fos/genetics , Plasmids
15.
Environ Health Perspect ; 88: 133-9, 1990 Aug.
Article in English | MEDLINE | ID: mdl-2125555

ABSTRACT

The products of the proto-oncogenes c-fos and c-jun form a tight protein complex that is a major component of the transcription factor AP1. To analyze the role of fos in the binding of this complex to the AP1 DNA recognition sequence and the mechanism of interaction in further detail, we have expressed a fos protein in E. coli using an expression vector containing the temperature-inducible lambda PL promoter and a synthetic translational start codon. The fos protein encoded by this construct (termed Baf) was enriched by biochemical purification techniques and was found to form a specific complex with c-jun obtained by in vitro transcription/translation. As shown in gel retardation assays, the baf/jun complex binds to the AP1 DNA recognition sequence with high affinity, while no significant binding was observed with either of the individual protein components, indicating cooperative DNA binding of the two proteins. The fact that the bacterial baf protein does not undergo glycosylation indicates that the post-translational modification of eukaryotic c-fos with N-acetylglucosamine is not required for the formation of a stable fos/jun/DNA complex.


Subject(s)
DNA-Binding Proteins/metabolism , Proto-Oncogene Proteins/metabolism , Transcription Factors/metabolism , Binding Sites , DNA-Binding Proteins/genetics , Escherichia coli/metabolism , Glycosylation , Protein Biosynthesis , Proto-Oncogene Proteins c-fos , Proto-Oncogene Proteins c-jun , Transcription Factors/genetics
16.
Cell ; 59(6): 999-1007, 1989 Dec 22.
Article in English | MEDLINE | ID: mdl-2513130

ABSTRACT

Fos protein can trans-activate AP-1-dependent gene expression and trans-repress the c-fos promoter. Although we find that trans-repression is enhanced by coexpression of c-Jun, it does not require any of the AP-1 or ATF sites in the mouse c-fos promoter. A major target for repression is the serum response element (SRE). Fos mutants with an impaired leucine zipper are defective in trans-repression and transformation, suggesting that these functions involve the formation of Fos protein complexes. In contrast, mutations that abolish DNA binding of Fos enhance trans-repression but destroy the transforming potential of Fos. In addition, v-Fos protein efficiently transforms but is unable to trans-repress. These findings point to different mechanisms involved in trans-activation and trans-repression and suggest that trans-repression of the type described here is neither sufficient nor required for Fos-induced transformation.


Subject(s)
Gene Expression Regulation, Neoplastic , Promoter Regions, Genetic , Proto-Oncogene Proteins/genetics , Proto-Oncogenes , Animals , Cell Line , Cell Transformation, Neoplastic , Cells, Cultured , DNA-Binding Proteins/genetics , Genes, Regulator , Mice , Oligonucleotide Probes , Plasmids , Protein-Tyrosine Kinases , Proto-Oncogene Proteins c-fos , Restriction Mapping , Transcriptional Activation , Transfection
17.
EMBO J ; 8(12): 3825-32, 1989 Dec 01.
Article in English | MEDLINE | ID: mdl-2511003

ABSTRACT

Fos and Jun proteins form a tight complex which binds specifically to the AP1 recognition sequence, a palindromic DNA element also referred to as the TPA responsive element (TRE). To elucidate the mechanism of Fos-Jun interaction with the TRE we have performed UV cross-linking studies using oligonucleotides where thymines were replaced with bromouracil. Our results indicate that both Fos and Jun directly contact the TRE but that the interaction of Fos and Jun with thymines in structurally equivalent positions in the two half sites of the TRE is different. In addition, we have carried out a comprehensive mutagenesis study of the TRE by introducing all possible point mutations plus thymine----uracil substitutions into the palindromic TRE core sequences and the adjacent nucleotides on both sides. The results of this analysis clearly show that the palindromic TRE is asymmetrical with respect to binding of Fos-Jun. We also show that a Fos protein complex with a homodimeric DNA binding site binds considerably less efficiently to TRE mutants with a perfect dyad symmetry compared with the binding to the wild-type TRE. This demonstrates that the asymmetrical recognition of the TRE is not due to the heterodimeric nature of the Fos/Jun complex but directly related to an asymmetry in the TRE sequence. The methyl groups of all four thymine residues within the TRE seem to be functionally crucial since thymine----uracil substitutions strongly reduce or abolish binding to Fos/Jun. The relevance of structurally equivalent methyl groups in the TRE core sequence is different, lending further support to the conclusion that the TRE is asymmetrical.


Subject(s)
DNA-Binding Proteins/metabolism , Proto-Oncogene Proteins/metabolism , Transcription Factors/metabolism , Animals , Base Sequence/drug effects , Electrophoresis, Polyacrylamide Gel , Methylation , Mice , Molecular Sequence Data , Mutation , Nucleic Acid Conformation , Proto-Oncogene Proteins c-fos , Proto-Oncogene Proteins c-jun , Tetradecanoylphorbol Acetate/pharmacology , Ultraviolet Rays
18.
Nature ; 341(6239): 243-5, 1989 Sep 21.
Article in English | MEDLINE | ID: mdl-2506451

ABSTRACT

The TPA (12-O-tetradecanoyl-phorbol-13-acetate) responsive element (TRE) is recognized by the inducible transcription factor AP1, a heterodimeric complex of Fos- and Jun-protein subunits, which each contain a specific structure known as the leucine zipper through which they interact. Studies using site-directed mutagenesis have shown that a basic region adjacent to the leucine zipper in Fos is crucial for the interaction of the Fos-Jun complex with the TRE, and probably represents a site of interaction with DNA. The functionally crucial amino acids in this region are almost completely conserved between Fos and Jun (refs 6, 7 and 11; M.N. and R.M., unpublished results), indicating the formation of a nearly symmetrical DNA-binding site in the Fos-Jun complex. Whereas Jun can form a homodimeric protein complex which binds to the TRE, Fos is unable to do so. The Fos-Jun heterodimer, however, possesses at least a 30-fold-higher affinity for the TRE than does the Jun-Jun homodimer, indicating cooperative binding. Because Fos cannot form a homodimer it is not known whether Fos specifically recognizes part of the TRE or has a different role in the binding of the Fos-Jun complex to DNA. Here we report that exchanging the leucine zipper in Fos with that of Jun generates a protein (termed psi-Fos) that can form a complex with Fos. This Fos-psi-Fos complex, and to a lesser extent a homodimeric psi-Fos complex, exhibits specific binding to the TRE. This finding strongly supports the hypothesis that Fos and Jun form a nearly symmetrical DNA-binding site that interacts with the palindromic TRE.


Subject(s)
DNA-Binding Proteins/metabolism , Proto-Oncogene Proteins/metabolism , Regulatory Sequences, Nucleic Acid , Transcription Factors/metabolism , Binding Sites , In Vitro Techniques , Macromolecular Substances , Oligonucleotides/metabolism , Proto-Oncogene Proteins c-fos , Proto-Oncogene Proteins c-jun , Recombinant Proteins/metabolism , Structure-Activity Relationship
19.
Nature ; 338(6216): 589-90, 1989 Apr 13.
Article in English | MEDLINE | ID: mdl-2494459

ABSTRACT

THE products of the cellular and retroviral fos genes associate with other nuclear proteins, among them the transcription factor AP1/Jun (see ref. 3 for a review). The Fos/Jun complex binds to a specific symmetrical DNA recognition sequence (termed TRE), thus stimulating transcription of the respective gene. Here, we show that two distinct regions in Fos are required for the formation of a Fos/Jun/TRE complex. These are the leucine zipper, involved in the association with Jun, and a directly adjacent basic region. Specific amino-acid substitutions in this basic, presumably alpha-helical, region abolish the interaction of Fos/Jun with the TRE but not the association of the two proteins. The functionally crucial amino acids are located in a region of Fos which is structurally similar to the putative DNA-binding sites in Jun and in the yeast transcriptional activator GCN4 (refs 15 and 16).


Subject(s)
Proto-Oncogene Proteins , Amino Acid Sequence , DNA-Binding Proteins , Leucine , Molecular Sequence Data , Mutation , Proto-Oncogene Proteins c-fos , Proto-Oncogene Proteins c-jun , Transcription Factors
20.
Cell ; 56(3): 507-16, 1989 Feb 10.
Article in English | MEDLINE | ID: mdl-2492453

ABSTRACT

Cellular and viral Fos proteins form a tight complex with other nuclear proteins, including the transcription factor and proto-oncogene AP-1/Jun. We have mapped the c-Jun binding site in Fos to a region containing regularly spaced leucine residues recently suggested to interdigitate with a similar structure in Jun. Substitution of single or multiple leucine residues or the alteration of leucine phasing by insertion of additional amino acids reduces or abolishes the binding to Jun, while the substitution of other amino acids has no noticeable effect. These results strongly suggest that the formation of a "leucine zipper" mediates the interaction between Fos and Jun. We also show that the differential binding of the various Fos mutants correlates with their potential to trans-activate AP-1-dependent transcription and to induce morphological transformation.


Subject(s)
DNA-Binding Proteins/genetics , Leucine , Proto-Oncogene Proteins/genetics , Proto-Oncogenes , Transcription Factors/genetics , Transcription, Genetic , Animals , Base Sequence , Cell Line , DNA-Binding Proteins/metabolism , HeLa Cells/metabolism , Humans , Kinetics , Molecular Sequence Data , Mutation , Oligonucleotide Probes , Protein Biosynthesis , Proto-Oncogene Mas , Proto-Oncogene Proteins/metabolism , Proto-Oncogene Proteins c-fos , Proto-Oncogene Proteins c-jun , Repetitive Sequences, Nucleic Acid , Transcription Factors/metabolism , Transfection
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