Characterization of centrosomal proteins Cep55 and pericentrin in intercellular bridges of mouse testes

Centrosomal protein 55 (Cep55), located in the centrosome in interphase cells and recruited to the midbody during cytokinesis, is essential for completion of cell abscission. Northern blot previously showed that a high level of Cep55 is predominantly expressed in the testis. In the present study, we examined the spatial and temporal expression patterns of Cep55 during mouse testis maturation. We found that Cep55, together with pericentrin, another centrosomal protein, were localized to the intercellular bridges (IBs) interconnecting spermatogenic cells in a syncytium. The IBs were elaborated as a double ring structure formed by an inner ring decorated by Cep55 or pericentrin and an outer ring of mitotic kinesin-like protein 1 (MKLP1) in the male germ cell in early postnatal stages and adulthood. In addition, Cep55 and pericentrin were also localized to the acrosome region and flagellum neck and middle piece in elongated spermatids, respectively. These results suggest that Cep55 and pericentrin are required for the stable bridge between germ cells during spermatogenesis and spermiogenesis.

Chitosan production from hemicellulose hydrolysate of corn straw: impact of degradation products on Rhizopus oryzae growth and chitosan fermentation

AIMS

To examine the potential use of hemicellulose hydrolysate (HH) for the production of chitosan by Rhizopus oryzae and investigate the influence of contents in HH on mycelia growth and chitosan synthesis.

METHODS AND RESULTS

Compared to xylose medium, HH enhanced mycelia growth, chitosan content and production of R. oryzae by 10.2, 64.5 and 82.1%, respectively. During sulfuric acid hydrolysis of corn straw, sugars (glucose, galactose, etc) and inhibitors (formic acid, acetic acid and furfural) were generated. Acetic acid (2.14 g l(-1)) and formic acid (0.83 g l(-1)) were stimulative, while furfural (0.55 g l(-1)) was inhibitory. Inhibitors, at different concentrations, increased the mycelia growth and chitosan production by 24.5-37.8 and 60.1-207.1%.

CONCLUSIONS

HH of corn straw is a good source for chitosan production. Inhibitors in HH, at proper concentrations, can enhance chitosan production greatly.

SIGNIFICANCE AND IMPACT OF THE STUDY

This work for the first time reported chitosan production from HH. Chitosan production can be greatly enhanced by cheap chemicals such as inhibitors in HH.

Polyglutamine-expanded ataxin-3 causes cerebellar dysfunction of SCA3 transgenic mice by inducing transcriptional dysregulation

In the present study, we prepared a SCA3 animal model by generating transgenic mice expressing polyglutamine-expanded ataxin-3-Q79. Ataxin-3-Q79 was expressed in brain areas implicated in SCA3 neurodegeneration, including cerebellum, pontine nucleus and substantia nigra. Ataxin-3-Q79 transgenic mice displayed motor dysfunction with an onset age of 5-6 months, and neurological symptoms deteriorated in the following months. A prominent neuronal loss was not found in the cerebellum of 10 to 11-month-old ataxin-3-Q79 mice displaying pronounced ataxic symptoms, suggesting that instead of neuronal demise, ataxin-3-Q79 causes neuronal dysfunction of the cerebellum and resulting ataxia. To test the involvement of transcriptional dysregulation in ataxin-3-Q79-induced cerebellar malfunction, microarray analysis and real-time RT-PCR assays were performed to identify altered cerebellar mRNA expressions of ataxin-3-Q79 mice. Compared to non-transgenic mice or mice expressing wild-type ataxin-3-Q22, 10 to 11-month-old ataxin-3-Q79 mice exhibited downregulated mRNA expressions of proteins involved in glutamatergic neurotransmission, intracellular calcium signaling/mobilization or MAP kinase pathways, GABA(A/B) receptor subunits, heat shock proteins and transcription factor regulating neuronal survival and differentiation. Upregulated expressions of Bax, cyclin D1 and CDK5-p39, which may mediate neuronal death, were also observed in ataxin-3-Q79 transgenic mice. The involvement of transcriptional abnormality in initiating the pathological process of SCA3 was indicated by the finding that 4 to 5-month-old ataxin-3-Q79 mice, which did not display neurological phenotype, exhibited downregulated mRNA levels of genes involved in glutamatergic signaling and signal transduction. Our study suggests that polyglutamine-expanded ataxin-3 causes cerebellar dysfunction and ataxia by disrupting the normal pattern of gene transcriptions.

Plasma hemostatic factors and endothelial markers in four racial/ethnic groups: the MESA study

BACKGROUND

Hemostatic factors and endothelial markers may play some role in racial/ethnic differences in cardiovascular disease (CVD) rates. However, little information exists on hemostatic factors and endothelial markers across racial/ethnic groups.

OBJECTIVES

To describe, in four American racial/ethnic groups (Caucasian, Black, Hispanic, and Chinese), mean levels of selected hemostatic factors and endothelial markers.

PATIENTS AND METHODS

Multi-ethnic Study of Atherosclerosis baseline data were used (participant age: 45-84 years). Sex-specific analysis of covariance models, and t-tests for pairwise comparisons, were used to compare means of factors and markers. Adjustments were made for demographics and traditional CVD risk factors. Differences were significant at P < 0.05.

RESULTS

Blacks had the highest levels of factor VIII, D-Dimer, plasmin-antiplasmin (PAP), and von Willebrand factor, among the highest levels of fibrinogen and E-selectin (women only), but among the lowest levels of intercellular adhesion molecule 1 (ICAM-1), and, in men, the lowest levels of plasminogen activator inhibitor-1 (PAI-1). Whites and Hispanics tended to have intermediate levels of factors and markers, although they had the highest levels of ICAM-1, and Hispanics had the highest mean levels of fibrinogen and E-selectin (women only). Chinese participants had among the highest levels of PAI-1, but the lowest, or among the lowest, of all other factors and markers. No soluble thrombomodulin differences were observed.

CONCLUSIONS

In this large cohort, hemostatic factor and endothelial marker mean levels varied by race/ethnicity, even after adjustment for traditional CVD risk factors.

Spatial and temporal expression profile of pinin during mouse development

SR and SR-related proteins are splicing regulators involved in embryo development in higher eukaryotes. Pinin (pnn) is a SR-related protein localized both within nucleus (nuclear pnn, N-pnn) and at desmosome of cell-cell adhesion (desmosomal pnn, D-pnn). To investigate the role of N-pnn during mouse embryo development, we examined its expression using Northern blot, real-time RT-PCR, immunostaining, and mRNA in situ hybridization (ISH). On Northern analysis, we found that pnn transcripts display two isoforms due to differential utilization of a polyadenylation site and exhibit tissue variable expression with thymus expressing the highest level of transcript. Analysis of pnn expression in mouse embryos revealed N-pnn expression starts from the two-cell fertilized egg stage and is ubiquitous at all stages of mouse embryo development. ISH and immunofluorescent staining of embryo cryosections showed that during mouse organogenesis N-pnn is highly expressed in the central nervous system. In addition, N-pnn was found to be highly expressed in the cortex region of thymus of E16.5 mouse fetus, while in the hepatic primordium the strongest signals were noted at E13.5 to E14.5 rather than at later developmental stages. Finally, we also determined the subcellular location of N-pnn in photoreceptors of developing retinas by nuclear fractionation and Western blot, because N-pnn displayed a staining pattern reminiscent of cytoplasmic proteins at the microscopic level in developing mouse photoreceptors. Altogether these data provide us with a better understanding of the tissue distribution pattern of N-pnn during mouse development.

Loss of Pnn expression attenuates expression levels of SR family splicing factors and modulates alternative pre-mRNA splicing in vivo

SR and SR-related proteins have been implicated as trans-acting factors that play an important role in splice selection and are involved at specific stages of spliceosome formation. A well-established property of SR protein splicing factors is their ability to influence selection of alternative splice sites in a concentration-dependent manner. Identification of molecules that regulate SR family protein expression is therefore of vital importance in RNA biology. Here we report that depletion of Pnn expression, a SR-related protein with functions involved in pre-mRNA splicing and mRNA export, induces reduced expression of a subset of cellular proteins, especially that of SR family proteins, including SC35, SRm300, SRp55, and SRp40, but not that of other nuclear proteins, such as p53, Mdm2, and ki67. Knocking down Pnn expression was achieved in vitro by siRNA transfection. Expression levels of SR and SR-related proteins in Pnn-depleted cells as compared to those in control cells were evaluated by immunofluorescent staining and Western blot with specific antibodies. In addition, we also demonstrate that loss of Pnn expression could modulate splice site selection of model reporter gene in vivo. Our finding is significant in terms of regulation of SR protein cellular concentration because it reveals that Pnn may play a general role in the control of the cellular amount of family SR proteins through down-regulation of its own expression, thereby providing us with a better understanding of the cellular mechanism by which Pnn fulfills its biological function.

Exercise effects on cardiac size and left ventricular diastolic function: relationships to changes in fitness, fatness, blood pressure and insulin resistance

OBJECTIVES

To determine exercise training effects on cardiac size and left ventricular (LV) diastolic function and relationships of exercise induced changes in physiological and body composition parameters with cardiac parameters.

DESIGN

Prospective, randomised controlled trial.

SUBJECTS

Men and women (63.6 (5.7) years, body mass index 29.5 (4.4) kg/m(2)) with untreated hypertension (systolic blood pressure (BP) 130-159 or diastolic BP 85-99 mm Hg).

MAIN OUTCOME MEASURES

Cardiac size and LV diastolic function, peak oxygen uptake (Vo(2)), muscle strength, general and abdominal fatness, and insulin resistance.

INTERVENTIONS

6 months of exercise training versus usual care.

RESULTS

When analysed by group at six months, cardiac size and LV diastolic function did not differ between exercisers (n = 51) and controls (n = 53), whereas exercisers had significantly higher peak Vo(2) (28 v 24 ml/kg/min) and strength (383 v 329 kg), and lower fatness (34% v 37%), diastolic BP (73 v 75 mm Hg) and insulin resistance (quantitative insulin sensitivity check index 0.35 v 0.34) versus controls (all p <or= 0.05). By regression analysis, among six month changes, increased peak Vo(2) and reduced abdominal fat were associated with increased cardiac size. Increased peak Vo(2) and reduced abdominal fat, BP and insulin resistance were associated with improved LV diastolic function. r Values ranged from 0.20 to 0.32 (p <or= 0.05).

CONCLUSIONS

When examined by group assignment, exercise had no effect on cardiac size or LV diastolic function. When individual variations in six month changes were examined, participants attaining the greatest increases in fitness and reductions in abdominal fatness, insulin resistance and BP showed a modest trend towards physiological hypertrophy characterised by increased cardiac size and improved LV diastolic function. These results suggest that decreased abdominal fatness may have a role in improving cardiovascular health.

Over-expression of SR-cyclophilin, an interaction partner of nuclear pinin, releases SR family splicing factors from nuclear speckles

Pre-mRNA splicing takes place within a dynamic ribonucleoprotein particle called the spliceosome and occurs in an ordered pathway. Although it is known that spliceosome consists of five small nuclear RNAs and at least 50 proteins, little is known about how the interaction among the proteins changes during splicing. Here we identify that SR-cyp, a Moca family of nuclear cyclophilin, interacts and colocalizes with nuclear pinin (pnn), a SR-related protein involving in pre-mRNA splicing. Nuclear pnn interacts with SR-cyp via its C-terminal RS domain. Upon SR-cyp over-expression, however, the subnuclear distribution of nuclear pnn is altered, resulting in its redistribution from nuclear speckles to a diffuse nucleoplasmic form. The diffuse subnuclear distribution of nuclear pnn is not due to epitope masking, accelerated protein turnover or post-translational modification. Furthermore, we find that SR-cyp regulates the subnuclear distribution of other SR family proteins, including SC35 and SRm300, in a similar manner as it does on nuclear pnn. This result is significant because it suggests that SR-cyp plays a general role in modulating the distribution pattern of SR-like and SR proteins, similar to that of Clk (cdc2-like kinase)/STY on SR family splicing factors. SR-cyp might direct its effect via either alteration of protein folding/conformation or of protein-protein interaction and thus may add another control level of regulation of SR family proteins and modification of their functions.

Nuclear Pnn/DRS protein binds to spliced mRNPs and participates in mRNA processing and export via interaction with RNPS1

Pnn/DRS protein is associated with desmosomes and colocalizes with splicing factors in nuclear speckled domains. The potential interaction of Pnn with RNPS1, a pre-mRNA splicing factor and a component of the exon-exon junction complex, prompted us to examine whether Pnn is involved in nuclear mRNA processing. By immunoprecipitation, we found that Pnn associates preferentially with mRNAs produced by splicing in vitro. Oligonucleotide-directed RNase H digestion revealed that Pnn binds to the spliced mRNAs at a position immediately upstream of the splice junction and that 5' splice site utilization determines the location of Pnn in alternatively spliced mRNAs. Immunoprecipitation further showed that Pnn binds to mRNAs produced from a transiently expressed reporter in vivo. Although associated with mRNPs, Pnn is a nuclear-restricted protein as revealed by the heterokaryon assay. Overexpression of an amino-terminal fragment of Pnn that directly interacts with RNPS1 leads to blockage of pre-mRNA splicing. However, although suppression of Pnn expression shows no significant effect on splicing, it leads to some extent to nuclear accumulation of bulk poly(A)(+) RNA. Therefore, Pnn may participate, via its interaction with RNPS1, in mRNA metabolism in the nucleus, including mRNA splicing and export.

Molecular characterization of a novel nucleolar protein, pNO40

We report the discovery and characterization of a novel nucleolar protein. This protein, referred to as pNO40 based on its molecular weight on SDS-PAGE, was identified through yeast two hybrid interaction screen of a human kidney cDNA library using pinin (pnn) protein as the bait. The deduced amino acids of pNO40 derived from cDNA cloning of diverse species display high conservation; 95% identify between human and mouse and 57.3% identity for human and zebrafish. Several distinct domains are discernable in the ORF of pNO40, including a ribosomal protein S1 RNA binding region, a CCHC type zinc finger, and clusters of basic amino acid representing potential nucleolar targeting signal. Immunostaining of endogenous or transfected pNO40 indicated that it is localized to nucleoli of diverse cultured cells, with some concentration in the granular component of nucleoli. Northern blot analysis demonstrated that pNO40 message is expressed ubiquitously across all tissues examined. Characterization of human and mouse pNO40 gene revealed that mouse gene spans 44 kb in length and contains 8 exons, while that of human is 68 kb in length and displays two isoforms generated by alternative splicing of the 5(')-untranslated region and differential usage of translation start site. Based on sequence features and its subcellular location, we predict that pNO40 is a novel nucleolar protein with function related to ribosome maturation and/or biogenesis.

Exercise blood pressure response is related to left ventricular mass

An exaggerated SBP response to exercise has been associated with increased left ventricular (LV) mass in some but not all studies. A total of 43 women and 34 men, aged 55-75 years, without evidence of cardiovascular disease, with a mean resting BP of 142+/-9/77+/-8 mmHg had their BP measured at rest and during maximal treadmill exercise. LV mass was measured using magnetic resonance imaging. LV mass was adjusted for lean body mass, which was assessed by dual energy X-ray absorptiometry. LV mass was within the normal range for the majority of the subjects. Among the resting and exercise BP indices, maximal SBP was the strongest correlate of LV mass (r=0.41, P<0.05). In multivariate analysis, maximal SBP was independently associated with LV mass after adjustment for lean body mass and gender, explaining 3% of the variance (P<0.05). Maximal exercise SBP is a modest but still independent predictor of LV mass in older persons with normal LV mass. These results raise the possibility that the SBP response to maximal exercise is an early marker of LV hypertrophy.

Fitness, fatness and activity as predictors of bone mineral density in older persons

OBJECTIVES

To determine relationships of bone mineral density (BMD) with fitness, physical activity, and body composition and fat distribution.

DESIGN

Cross-sectional.

SETTING

General Clinical Research Center, Johns Hopkins Bayview Medical Center, Baltimore, Maryland.

SUBJECTS

Men (n = 38) and women (n = 46), aged 55-75 years with high normal blood pressure or mild hypertension but otherwise healthy.

METHODS

Aerobic fitness (oxygen uptake) on a treadmill, muscle strength by one-repetition maximum, activity by questionnaire, abdominal obesity by magnetic resonance imaging; anthropometrics, and body composition by dual energy X-ray absorptiometry (DXA) which measured total fat and lean mass, and BMD for the total skeleton, lumbar spine (L1-L4) and total hip.

RESULTS

Aerobic fitness did not correlate with BMD. Using multivariate analysis to ascertain independent contributions to the variance in BMD, in women, with adjustment for hormone replacement therapy (HRT), total skeleton BMD was independently related to muscle strength and abdominal total fat; total hip BMD to body weight; lumbar spine BMD to abdominal total fat. HRT also influenced BMD in the lumbar spine. In men, lumbar spine BMD was independently related to abdominal total fat physical activity and total hip BMD related to lower body strength. P < 0.05 for all of these correlations.

CONCLUSIONS

Abdominal obesity and muscle strength emerge as predominant correlates of BMD in older persons with stronger relationships seen in women. Body weight and HRT also explained portions of the variance in BMD in women. Whether abdominal obesity is simply a marker for general obesity or has independent protective effects on bone is yet to be determined.

Modulation of alternative pre-mRNA splicing in vivo by pinin

Pre-mRNA splicing occurs in a large macromolecular RNA-protein complex called the spliceosome. The major components of the spliceosome include snRNP and SR proteins. We have previously identified an SR-like protein, pinin (pnn), which is localized not only in nuclear speckles but also at desmosomes. The nuclear localization of pnn is a dynamic process because pnn can be found not only with SR proteins in nuclear speckles but also in enlarged speckles following treatment of cells with RNA polymerase II inhibitors, DRB, and alpha-amanitin. Using adenovirus E1A and chimeric calcitonin/dhfr construct as a splicing reporter minigene in combination with cellular cotransfection, we found that pnn regulates alternative 5(') and 3(') splicing by decreasing the use of distal splice sites. Regulation of 5(') splice site choice was also observed for RNPS1, a general splicing activator that interacts with pnn in nuclear speckles. The regulatory ability of pnn in alternative 5(') splicing, however, was not dependent on RNPS1 and a pnn mutant, lacking the N-terminal 167 amino acids, behaved like a dominant negative species, inhibiting E1A splicing when applied in splicing assays. These results provide direct evidence that pnn functions as a splicing regulator which participates itself directly in splicing reaction or indirectly via other components of splicing machinery.

The relationship between vascular wall shear stress and flow-mediated dilation: endothelial function assessed by phase-contrast magnetic resonance angiography

OBJECTIVES

We sought: 1) to investigate the relationship between vascular wall shear stress and flow-mediated dilation (FMD) in humans, and 2) to investigate whether this relationship could explain why FMD is greater in small arteries.

BACKGROUND

Arterial wall shear stress (WSS) is considered to be the primary stimulus for the endothelial-dependent FMD response. However, the relationship between WSS and FMD has not been investigated in humans. Furthermore, FMD is greater in small arteries, though the reasons for this phenomenon are unclear.

METHODS

Using phase-contrast magnetic resonance angiography (PMRCA), we measured hyperemic WSS and FMD in 18 healthy volunteers. Peak systolic WSS was calculated assuming a blunted parabolic velocity profile. Diameter by PCMRA and by ultrasound was compared in nine subjects.

RESULTS

Flow-mediated dilation was linearly proportional to hyperemic peak systolic WSS (r = 0.79, p = 0.0001). Flow-mediated dilation was inversely related to baseline diameter (r = 0.62, p = 0.006), but the hyperemic peak WSS stimulus was also inversely related to baseline diameter (r = 0.47, p = 0.049). Phase-contrast magnetic resonance angiography and ultrasound diameters were compared in nine subjects and correlated well (r = 0.84, p < 0.0001), but diameter by PCMRA was greater (4.1 +/- 0.7 mm vs. 3.7 +/- 0.5 mm, p = 0.009).

CONCLUSION

Arterial FMD is linearly proportional to peak hyperemic WSS in normal subjects. Thus, the endothelial response is linearly proportional to the stimulus. Furthermore, the greater FMD response in small arteries is accounted for, at least partially, by a greater hyperemic WSS stimulus in small arteries. By allowing the calculation of vascular WSS, which is the stimulus for FMD, and by imaging a fixed arterial cross-section, thus reducing operator dependence, PCMRA enhances the assessment of vascular endothelial function.

A model of interfacial inactivation for papain in aqueous organic biphasic systems

A model was proposed to describe the effects of the main factors in aqueous-organic two-liquid-phase media on the stability of papain. The relationships between the half-life of papain activity and these factors including interfacial tension, stirring rate, phase volume ratio and temperature were investigated. The results showed that these factors had notable effects on papain stability except temperature. The correlation coefficient between the model and the experimental data were 0.829, which indicated the model is practicable.

ChoICE PT wire for recanalization of chronically occluded coronary arteries: multiple wires in one?

Percutaneous transluminal coronary angioplasty (PTCA) of chronic total occlusions may be technically difficult and the success rate is limited despite increasing operator experience and improvements in PTCA hardware. The number of guidewires required to cross totally occluded lesions is higher than that for stenotic lesions. The ChoICE polymer-tip (PT) wire (Boston Scientific/Scimed, Inc., Maple Grove, Minnesota) is a relatively new stainless-steel core wire with a hydrophilic-coated polyurethane tip. Though never described in the literature, we found that the distal 4 cm of the wire can be cut and reshaped according to the operator's needs. Thus, instead of reshaping a kinked tip or using another new wire, the former being time-consuming and the latter expensive, one can simply cut off the kinked tip and start again with a "new wire." As the tip is resected, the wire becomes progressively more "intermediate-like" and "standard-like." We report our experience with the ChoICE PT wire in 50 consecutive cases of chronic total occlusions. The cumulative crossing success rates were 13/50 (26%) before any resections, 24/50 (48%) after 1 resection, 41/50 (82%) after 2 resections and 42/50 (84%) after 3 resections. There were no perforations, deaths, myocardial infarctions or need for bypass surgery. Our findings suggest that successful recanalization of chronic total occlusions can be achieved with a high success rate using the ChoICE PT wire. A strategy of progressively resecting the more floppy and kinked distal end can provide multiple uses from a single wire, optimizing recanalization success and obviating the need for additional wires.

Awareness, perception, and knowledge of heart disease risk and prevention among women in the United States. American Heart Association Women's Heart Disease and Stroke Campaign Task Force

CONTEXT

One of 2 women in the United States dies of heart disease or stroke, yet women are underdiagnosed and undertreated for these diseases and their risk factors. Informed decisions to prevent heart disease and stroke depend on awareness of risk factors and knowledge of behaviors to prevent or detect these diseases.

OBJECTIVE

Assess (1) knowledge of risks of heart disease and stroke and (2) perceptions of heart disease and its prevention among women in the United States.

DESIGN AND SETTING

Telephone survey conducted in 1997 of US households, including an oversample of African American and Hispanic women.

PARTICIPANTS

One thousand respondents 25 years or older; 65.8% white, 13.0% African American, and 12.6% Hispanic.

MAIN OUTCOME MEASURES

Knowledge of heart disease and stroke risks, perceptions of heart disease, and knowledge of symptoms and preventive measures.

RESULTS

Only 8% of the respondents identified heart disease and stroke as their greatest health concerns; less than 33% identified heart disease as the leading cause of death. More women aged 25 to 44 years identified breast cancer as the leading cause of death than women 65 years or older. Women aged 25 to 44 years indicated they were not well informed about heart disease and stroke. Although 90% of the women reported that they would like to discuss heart disease or risk reduction with their physicians, more than 70% reported that they had not.

CONCLUSIONS

Most women do not perceive that heart disease is a substantial health concern and report that they are not well informed about their risk. Age influenced knowledge to a greater extent than ethnicity. Programs directed at young women that address the effects of lifestyle behaviors on long-term health are needed. Better communication between physicians and patients is also warranted.

Characterization of the gene encoding pinin/DRS/memA and evidence for its potential tumor suppressor function

Several cell adhesion-related proteins have been shown to act as tumor-suppressors (TS) in the neoplastic progression of epithelial-derived tumors. Pinin/DRS/memA was first identified in our laboratory and it was shown to be a cell adhesion-related molecule. Our previous study demonstrated that restoration of pinin expression in transformed cells not only positively influenced cellular adhesive properties but also reversed the transformed phenotype to more epithelial-like. Here, we show by FISH analysis that the gene locus for pinin is within 14q13. The alignment of the pinin gene with STS markers localized the gene to the previously identified TS locus D14S75-D14S288. Northern analyses revealed diminished pinin mRNA in renal cell carcinomas (RCC) and certain cancer cell lines. Immunohistochemical examination of tumor samples demonstrated absent or greatly reduced pinin in transitional cell carcinoma (TCC) and RCC tumors. TCC-derived J82 cells as well as EcR-293 cells transfected with full-length pinin cDNA demonstrated inhibition of anchorage-independent growth of cells in soft agar. Furthermore, methylation analyses revealed that aberrant methylation of pinin CpG islands was correlated with decreased/absent pinin expression in a subset of tumor tissues. These data lend significant support to the hypothesis that pinin/DRS/memA may act as a tumor suppressor in certain types of cancers.

Antibodies differentiate desmosome-form and nucleus-form pinin: evidence that pinin is a moonlighting protein with dual location at the desmosome and within the nucleus

Pinin is a desmosome-associated protein occurring in epithelia, cardiac muscle, and meninges. This molecule was found to be capable of enhancing cell junction formation and thought to play a key role in reorganization and stabilization of the desmosome-intermediate filament complex in epithelial cells (J. Cell Biol. (1996) 135, 1027-1042). Recently a protein, claimed to be localized exclusively in the nucleus, however, with amino acid sequence identical to pinin, was reported (E. J. Cell Biol. (1998) 75, 295-298). Here I present evidence that pinin exists simultaneously at the desmosome and within the nucleus by generating location-specific monoclonal antibodies. Although the desmosome-form (d-form) and the nucleus-form (n-form) pinin share identical amino acid sequences as demonstrated by cDNA library screening and DNA sequencing, they exhibit remarkably different biochemical properties, reflecting the apparent different multiprotein nature of their differential cellular locations. In addition, the d-form pinin is characterized by a dynamic transport process which involves the gradual diminishing of nuclear materials relative to enhanced anchoring of pinin to the desmosome upon mature cells. Finally I demonstrate that pinin exists in two forms of different gene product: pinin1 and pinin2. These data argue strongly against the statement that pinin is an exclusive nuclear protein and support the notion that pinin is a moonlighting protein with more than one function as a consequence of its dual cellular location.

Methylation of the estrogen receptor gene is associated with aging and atherosclerosis in the cardiovascular system

OBJECTIVE

Methylation of the promoter region of the estrogen receptor gene alpha (ER alpha) occurs as a function of age in human colon, and results in inactivation of gene transcription. In this study, we sought to determine whether such age-related methylation occurs in the cardiovascular system, and whether it is associated with atherosclerotic disease.

METHODS

We used Southern blot analysis to determine the methylation state of the ER alpha gene in human right atrium, aorta, internal mammary artery, saphenous vein, coronary atherectomy samples, as well as cultured aortic endothelial cells and smooth muscle cells.

RESULTS

An age related increase in ER alpha gene methylation occurs in the right atrium (range 6 to 19%, R = 0.36, P < 0.05). Significant levels of ER alpha methylation were detected in both veins and arteries. In addition, ER alpha gene methylation appears to be increased in coronary atherosclerotic plaques when compared to normal proximal aorta (10 +/- 2% versus 4 +/- 1%, P < 0.01). In endothelial cells explanted from human aorta and grown in vitro, ER alpha gene methylation remains low. In contrast, cultured aortic smooth muscle cells contain a high level of ER alpha gene methylation (19-99%).

CONCLUSIONS

Methylation associated inactivation of the ER alpha gene in vascular tissue may play a role in atherogenesis and aging of the vascular system. This potentially reversible defect may provide a new target for intervention in heart disease.

[Studies on preparation of L-phenylalanine from phenylpyruvic acid by E. coli EP8-10]

E. coli EP8-10 was selected from the soil. It was able to produce the transaminase with high activity when it was cultivated on the medium containing peptone and beef extract. Optimum conditions of enzyme reaction was: phenylpyruvic acid's concentration of 0.3-0.5 mol/L, L-Asptaric acid used as amino donor, pH 8.5 37 degrees C. When phenylpyruvic acid was 0.3 mol/L, 48 g/L L-phenylalanine was produced after 6 h with 97% conversion rate.