Direct evidence of high DNA binding activity of transcription factor AP-1 in rheumatoid arthritis synovium

Green fluorescent protein (GFP) is increasingly being used in plant biology from the cellular level to whole plant level. At the cellular level, GFP is being used as an in vivo reporter to assess frequency of transient and stable transformation. GFP has also proven to be an invaluable tool in monitoring trafficking and subcellular localization of protein. At the organ level and up, many exciting applications are rapidly emerging. The development of brighter GFP mutants with more robust folding properties has enabled better macroscopic visualization of GFP in whole leaves and plants. One interesting example has been the use of GFP to monitor virus movement in and among whole plants. GFP is also emerging as a powerful tool to monitor transgene movement and transgenic plants in the field. In a proof-of-concept study, tobacco was transformed with a modified version of the GFP gene controlled by a constitutive (35S) promoter. GFP expression in progeny plants ranged from 0% to 0.5%, and approximately 0.1% GFP was the minimal amount needed for unambiguous macroscopic detection. GFP is the first truly in vivo reporter system useful in whole plants, and we project its usefulness will increase even further as better forms of GFP genes become available.     

(-)-Epigallocatechin-3-gallate inhibition of ultraviolet B-induced AP-1 activity

Green tea polyphenols have been shown to inhibit cancer in a variety of tumor models, including ultraviolet B (UVB)-induced non-melanoma skin cancer. In green tea extracts, the major dry mass constituent is the family of catechins, of which (-)-epigallocatechin-(3)-gallate (EGCG) is considered to be important for the chemopreventive activity. EGCG has been shown to have antioxidant properties, but there has been little progress toward identifying the specific targets and mechanisms of its action. Using cultured human keratinocytes, we show that UVB-induced AP-1 activity is inhibited by EGCG in a dose range of 5.45 nM to 54.5 microM. EGCG is effective at inhibiting AP-1 activity when applied before, after or both before and after UVB irradiation. EGCG also inhibits AP-1 activity in the epidermis of a transgenic mouse model. This work begins to define a mechanism by which EGCG could be acting to inhibit UVB-induced tumor formation.     

Levodopoa but not bromocriptine induces AP-1 and creb DNA-binding activity in the dopamine-depleted striatum of the rat

To elucidate the neurochemical mechanism that underlies the effect of anti-parkinsonian agents on motor activities in the dopamine-depleted striatum, we evaluated AP-I and CREB DNA-binding activity in the striatum of 6-hydroxydopamine-lesioned rats by use of a gel mobility-shift assay. Rats with a unilateral lesion of the nigrostriatal dopamine pathway were injected i.p. with either SKF38393 (a DI receptor agonist), bromocriptine (a D2 receptor agonist), or levodopa (a Dl/D2 receptor agonist). Each treatment increased the number of rotational responses of rats contralateral to the lesioned side. However, only SKF38393 and levodopa increased AP-I and CREB DNA-binding activity in the dopamine-depleted striatum. As with the expression of c-fos, supersensitive DI receptors may play a key role in the enhanced induction of AP-I and CREB DNA-binding activity in the dopamine-depleted striatum. Supershift analysis revealed that c-Fos; and Jun family proteins are the main components for AP-1 induced in the dopamine-depleted striaturn by SKF38393 or levodopa.     

Modulation of JunD.AP-1 DNA binding activity by AP-1-associated factor 1 (AF-1)

AP-1-associated factor 1 (AF-1), is a novel protein complex that dramatically enhances the assembly of JunD-containing dimers onto AP-1 consensus sites. We describe the partial purification of AF-1 from nuclear extracts of the T-cell line MLA 144 by ionic, hydrophobic and gel filtration chromatography. AF-1 is a DNA-binding protein composed of low molecular mass polypeptides of 7-17 kDa that exists in solution as a 34-kDa complex. JunD interactions with DNA are accelerated in the presence of AF-1 through the formation of a true tri-molecular complex with JunD dimers and DNA that assembles much more rapidly on DNA than JunD alone. DNA binding analysis of AF-1 interaction with JunD.AP-1 and DNA shows that AF-1 increases the DNA binding affinity of JunD for AP-1 sites over 100-fold. DNA cleavage footprint analysis of isolated AF-1.JunD DNA complexes shows that the ternary complex makes nearly twice as many contacts with DNA than JunD dimers alone. AF-1 interacts readily, but differentially with Jun homodimers and Jun.Fos heterodimers. These findings distinguish AF-1 as a significant protein-specific modulator of AP-1.JunD in T-cells.     

Inhibition of ultraviolet B-induced activator protein-1 (AP-1) activity by aspirin in AP-1-luciferase transgenic mice

Aspirin is under consideration as a promising chemopreventative agent for human cancers. To study the usefulness of aspirin as a chemopreventative agent for UV-induced human skin cancer, we investigated the effect of aspirin on UVB-induced activator protein-1 (AP-1) activity. In the JB6 cell culture system, aspirin or sodium salicylate (SA) inhibited UVB-induced AP-1 activity in a dose-dependent manner; this inhibitory effect occurred only in cells pretreated with aspirin or SA before UVB irradiation but not cells treated with aspirin or SA after UVB irradiation. Furthermore, these inhibitory effects on UVB-induced AP-1 activity appeared to be mediated through blocking of activation of MAP kinase family members, including extracellular signal-regulated protein kinases, c-Jun N-terminal kinases, and p38. It was not due to absorption of UVB light by aspirin. In the skin of AP-1-luciferase transgenic mice, UVB irradiation induced a rapid increase in AP-1 activity, which reached the peak at 48 h post-UVB irradiation. The topical pretreatment of mouse skin with aspirin markedly blocked the UVB-induced AP-1 transactivation in vivo. These data provide the first evidence that aspirin and SA are inhibitors of UV-induced signal transduction and thus could be used as a chemopreventative agent for skin cancer.     

Role of the transcription factor AP-1 in melanoma differentiation (review)

Despite increasing evidence that pain is a problem with which many in their later years must contend, little is known about the experience of community-dwelling seniors who require the assistance of home nursing services to remain independent and functional in their homes. This study investigated the prevalence and experience of pain among seniors who were recipients of home nursing services. The study was guided by the World Health Organization Classification of Impairment, Disability and Handicap. Face to face interviews were conducted with 66 individuals who reported whether they were often troubled by pain and/or had experienced pain of a noteworthy nature within the 2 weeks prior to the interview. In addition, they responded to standardized questions about their pain experience and their levels of disability and functional competence. Findings revealed that although three-quarters of respondents reported pain, there was no association between pain and measures of disability. Findings, however, revealed an association between pain and measures of functional competence, more specifically, global function, level of depressive symptomatology, sleep impairment and satisfaction with life. Implications for nursing include the need for a heightened awareness of the prevalence of pain in community-dwelling older adults and the development of assessment and intervention strategies that support their quality of life.     

The oestrogen receptor regulates NFkappaB and AP-1 activity in a cell-specific manner

It has recently been identified the PEPT2 cDNA encodes the high affinity proton-coupled peptide transporter in rabbit kidney cortex. PEPT2 represents a 729 amino acid protein with 12 putative transmembrane domains that mediates H+/H3O+ dependent electrogenic transmembrane transport of di- and tripeptides and of selected peptidomimetics. Here the functional expression of PEPT2 in the methylotropic yeast Pichia pastoris is described under the control of a methanol inducible promoter. Western blot analysis of Pichia cell membranes prepared from a recombinant clone identified a protein with an apparent molecular mass of about 85-87 kDa. Peptide uptake into cells expressing PEPT2 was up to 80 times higher than in control cells. Cells of recombinant clones showed a saturable peptide transport activity for the hydrolysis resistant dipeptide 3H-D-Phe-Ala with an app. K0.5 of 0.143 +/- 0.016 mM. Inhibition of 3H-D-Phe-Ala uptake by selected di- and tripeptides and beta-lactam antibiotics revealed the same substrate specificity as obtained in renal membrane vesicles or for PEPT2 when expressed in Xenopus laevis oocytes. A novel fluorescence based assay for assessing transport function based on a coumarin-labeled fluorescent peptide analogue has also been developed. Moreover, using a histidyl auxotrophe strain a PEPT2 expressing cell clone in which transport function can be monitored by a simple yeast growth test was established. In conclusion, this is one of only a few reports on successful functional expression of mammalian membrane transport proteins in yeast. The high expression level will provide a simple means for future studies either on the structure-affinity relationship for substrate interaction with PEPT2 or for selection of mutants generated by random mutagenesis.     

Estrogen regulation of the insulin-like growth factor I gene transcription involves an AP-1 enhancer

As a step toward elucidating the physiological role of insulin-like growth factor-I (IGF-I) in mediating estrogen action, we sought to determine the molecular basis of the phenomenon. In HepG2 cells expressing exogenous estrogen receptors (ER), a reporter gene plasmid containing 600 base pairs of the chicken IGF-I promoter enhanced expression of luciferase 8.6-fold in response to 10(-6) M 17 beta-estradiol, indicating that the IGF-I promoter is a target of estrogen regulation. Although no conventional estrogen-responsive element was identified within the promoter fragment, the AP-1 motif located therein was shown to be essential; the estrogen-responsive enhancement of the Fos-Jun binding to the AP-1 motif, which takes place by means of post-translational modification, mediates the estrogen action. A direct or indirect interaction between the estrogen-ER complex and the Fos-Jun complex seems to facilitate the Fos-Jun binding to the target DNA. Although ER binding to the target DNA was not considered to be involved in the signaling pathway, the DNA binding domain-deficient ER did not mediate the phenomenon, providing support for the existence of a unique function of the DNA binding domain of ER in facilitating some protein-protein interaction. In conclusion, our present observations demonstrate that the chicken IGF-I gene promoter is controlled by estrogen through a unique pathway involving Fos, Jun, and the DNA binding domain of ER.     

Light-induced variations in AP-1 binding activity and composition in the rat suprachiasmatic nucleus

Expression of immediate early genes, including fos-like and jun-like genes, in the suprachiasmatic nucleus is believed to be part of the mechanism for photic entrainment of circadian rhythms to the environmental light/dark cycle. However, the effects of a light stimulus on activating protein-1 (AP-1) complexes in the suprachiasmatic nucleus remain unclear. The photic regulation of AP-1 DNA-binding activity and composition in the rat suprachiasmatic nucleus was evaluated by using an electrophoretic mobility shift assay. A light pulse given during subjective night induced an increase in AP-1 binding activity when either nuclear or whole-cell extracts from suprachiasmatic nuclei were used. Under constant dark conditions, proteins that are predominant components of AP-1 complexes are Fra-2 and Jun-D. Under light stimulation, c-Fos and Jun-B consistently increased, as expected, but this was also the case for Fra-2, Jun-D, and c-Jun, although to a lesser extent. An immunocytochemical study of the Fra-2 expression pattern demonstrated the presence of the protein in the ventrolateral as well as in the dorsomedial subdivisions of the suprachiasmatic nucleus. Light regulation of Fra-2 immunoreactivity, however, appeared to be restricted to the ventrolateral subdivision. It is concluded that light may be acting both by increasing constitutive AP-1 complexes and by inducing the expression of specific complexes.     

The effects of measles virus persistent infection on AP-1 transcription factor binding in neuroblastoma cells

"Aerobiologia 2.0" is a simple computer program created to handle the pollen data collected every 2 hrs and daily by aerobiological monitoring stations equipped with Hirst-type spore traps. "Aerobiologia 2.0" runs on Windows 3.1 and is compatible with other programs that run on this operating system. The program was developed to store and process pollen data through a few straightforward operations. An unlimited calendar automatically calculates the day of the week. The pollen dictionary, which can hold up to 1216 different pollen types, may be modified or changed completely. Concentrations for every pollen type (in pollen grains/m3) are automatically recorded daily and every 2 hrs. 10-day and monthly sums are also calculated. The percentage of selected types, groups, or families of pollen collected each day, every 10 days, and monthly is quickly available. Pollen calendars and spectra in 24-hr, 10-day, monthly, tri-monthly, half-year, and yearly periods are readily produced. As soon as it is entered, the pollen data are saved on hard disk. A year's worth of data can be saved on a single 1.44 M byte floppy disk. Aerobiologia 2.0 is being used successfully to process the aeropollen data collected at the two monitoring stations managed by our Palynological Laboratory.