Protein kinase A activity and protein phosphorylation during the mouse sperm acrosomal reaction

Using two-dimensional gel electrophoresis, changes in protein phosphorylation caused by cyclic nucleotide-dependent protein kinases were analyzed with or without exposure to a protein kinase inhibitor, H-8, during the mouse sperm acrosomal reaction. The acrosomal reaction, induced by the treatment of sperm with dibutyryl cyclic AMP or dibutyryl cyclic GMP, was inhibited by H-8. The activities of cyclic AMP-dependent protein kinase (PKA) and cyclic GMP-dependent protein kinase induced by the sperm extract were also inhibited by H-8. When endogenous PKA in sperm was activated by the addition of cyclic AMP, a 45-kDa protein spot identified by electrophoresis indicated the occurrence of phosphorylation in vivo. Furthermore, the enhanced phosphorylation of the 45-kDa protein spot was inhibited by H-8. These results suggest that the PKA-catalyzed phosphorylation of the 45-kDa protein may be involved in the regulation of the mouse sperm acrosomal reaction.

Proteomics of the rice cell: systematic identification of the protein populations in subcellular compartments

Despite recent progress in sequencing the complete genome of rice ( Oryza sativa), the proteome of this species remains poorly understood. To extend our knowledge of the rice proteome, the subcellular compartments, which include plasma membranes (PM), vacuolar membranes (VM), Golgi membranes (GM), mitochondria (MT), and chloroplasts (CP), were purified from rice seedlings and cultured suspension cells. The proteins of each of these compartments were then systematically analyzed using two-dimensional (2D) electrophoresis, mass spectrometry, and Edman sequencing, followed by database searching. In all, 58 of the 464 spots detected by 2D electrophoresis in PM, 43 of the 141 spots in VM, 46 of the 361 spots in GM, 146 in the 672 spots in MT, and 89 of the 252 spots in CP could be identified by this procedure. The characterized proteins were found to be involved in various processes, such as respiration and the citric acid cycle in MT; photosynthesis and ATP synthesis in CP; and antifungal defense and signal systems in the membranes. Edman degradation revealed that 60-98% of N-terminal sequences were blocked, and the ratios of blocked to unblocked proteins in the proteomes of the various subcellular compartments differed. The data on the proteomes of subcellular compartments in rice will be valuable for resolving questions in functional genomics as well as for genome-wide exploration of plant function.

Microarray analysis of brassinosteroids- and gibberellin-regulated gene expression in rice seedlings

In order to understand the molecular mechanisms by which two types of phytohormones, brassinosteroids (BRs) and gibberellins (GAs), regulate plant growth and development, a cDNA microarray was made containing 4000 clones randomly selected from a rice cDNA library constructed from RNA isolated from seedlings treated with GA(3) and brassinolide (BL). The array was then probed to identify differences in expression using labelled cDNAs prepared from treated and control seedlings. Nine and 29 unique cDNA clones were up-regulated, while 32 and 42 unique cDNA clones were down-regulated by BL and GA(3), respectively. The predicted products of these BL- and GA-regulated genes fall into such functional categories as signal transduction, transcription, metabolism, cellular organization, and defense or anti-stress responses. Northern analysis of the selected BL- and GA(3)-regulated genes not only confirmed their BL or GA(3) dose dependent expression, but also revealed significant differences in the degree of expression in different organs and in response to other phytohormones. These results demonstrate that BR and GA influence growth and development by coordinately regulating the expression of specific groups of genes.

Proteome analysis of rice tissues by two-dimensional electrophoresis: an approach to the investigation of gibberellin regulated proteins

Protein databases constructed using high-resolution two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) were used to explore the proteome expressed in various rice tissues. Proteins from leaf sheath, root, and cultured suspension cells were systematically analyzed using 2D-PAGE, mass spectrometry and Edman sequencing, followed by database searching. In all, 79 of the 431 spots detected by 2D-PAGE in the leaf sheath, 73 of the 508 spots in the root and 140 of the 962 spots in the cultured suspension cells could be identified. Protein lists were constructed for each tissue and used to investigate the effects of gibberellin (GA) treatment. In the leaf sheath, root and cultured suspension cells, 8, 21, and 14 of the identified proteins, respectively, were regulated by GA. These proteins included polypeptides involved in general metabolism, energy production, transcriptional regulation and signal transduction in the leaf sheath; in metabolism and defense in the root; and in metabolism, energy production, cell growth, defense and signal transduction in the cultured suspension cells. These results indicate that the proteome databases assembled in these studies will be useful for the rapid assessment of changes in protein content in specific tissues, and that proteins regulated by GA may play a significant role in tissue growth.

Expression of the exocytotic protein syntaxin in mouse oocytes

Syntaxin is an integral membrane protein that is involved in membrane fusion. The exocytosis of the contents of cortical granules, secretory vesicles located in the cortex of an egg, modify the extracellular environment to block additional spermatozoa from penetrating the newly fertilized egg. The aim of this study was to characterize syntaxin expression in mouse oocytes, and to determine the specific isoform that is expressed. Syntaxin was demonstrated in the mouse ovary and in mouse oocytes by both western blot and reverse transcription-polymerase chain reaction analyses. Syntaxin 4 was specifically expressed in metaphase II oocytes. Syntaxin was also immunolocalized within metaphase II oocytes and one-cell embryos with pronuclei using laser scanning confocal microscopy. In metaphase II oocytes, syntaxin was located on the plasma membrane and in the cortex, where cortical granules are present, but was not seen at sites free of cortical granules. In one-cell embryos, no cytoplasmic region was free of syntaxin immunoreactivity. Immunoelectron microscopy detected syntaxin on both the plasma membrane and the vesicle membranes in mouse metaphase II oocytes. In conclusion the results indicate that syntaxin 4 co-localizes with cortical granules and participates in membrane fusion and exocytosis during the cortical reaction.

Antitumor effect of vitamin B6 and its mechanisms

Epidemiological studies have reported an inverse association between vitamin B(6) intake and colon cancer risk. Our recent study has been conducted to examine the effect of dietary vitamin B(6) on colon tumorigenesis in mice. Mice were fed diets containing 1, 7, 14 or 36 mg/kg pyridoxine for 22 weeks, and given a weekly injection of azoxymethane (AOM) for the initial 10 weeks. Compared with the 1 mg/kg pyridoxine diet, 7, 14 and 35 mg/kg pyridoxine diets significantly suppressed the incidence and number of colon tumors, colon cell proliferation and expressions of c-myc and c-fos proteins. Supplemental vitamin B(6) lowered the levels of colonic 8-hydroxyguanosine (8-OHdG), 4-hydroxy-2-nonenal (4-HNE, oxidative stress markers) and inducible nitric oxide (NO) synthase protein. In an ex vivo serum-free matrix culture model using rat aortic ring, supplemental pyridoxine and pyridoxal 5'-phosphate (PLP) had antiangiogenic effect. The results suggest that dietary vitamin B(6) suppresses colon tumorigenesis by reducing cell proliferation, oxidative stress, NO production and angiogenesis.

Immunohistochemical expression of CA19-9 and CA125 in mucoepidermoid and adenoid cystic carcinomas of the salivary gland

This study examined the immunohistochemical expression of carbohydrate antigens CA19-9 and CA125 and their relationship to various biological parameters in 27 mucoepidermoid carcinomas (MEC) and 18 adenoid cystic carcinomas (ACC) arising from salivary glands. The series showed higher immunopositivity for CA125 (67% for MEC; 33% for ACC) than for CA19-9 (59% for MEC; 11% for ACC). CA19-9 epitope was mainly expressed in cystic (MEC) and cribriform/tubular (ACC) components of carcinoma tissues. Solid components in MEC occasionally showed positive staining for CA19-9. CA125 was evenly expressed in both ACC and MEC tissues regardless of their different histological components. The positive expression of CA19-9 and CA125 in the carcinoma tissues did not influence the clinical course of patients with MEC and ACC. A significant relationship was only demonstrated between the immunohistochemical expression of CA125 and the low proliferative activity (LI) evaluated by Ki-67 immunohistochemistry. However, no significant relationship was found between LI and the patients' clinical course. These results suggest that the immunostaining for CA19-9 and CA125 provide no reliable data to predict the clinical course of patients with MEC and ACC of the salivary glands.

Passive smoking at home and cancer risk: a population-based prospective study in Japanese nonsmoking women

OBJECTIVES

To investigate the relationship between passive smoking at home and the incidence of various cancers in a population-based prospective study.

METHODS

The subjects were 9675 Japanese lifelong nonsmoking women aged over 40 years who lived in three municipalities of Miyagi Prefecture, and completed a self-administration questionnaire in 1984. During 9 years of follow-up, 426 cancers were identified by record linkage to the population-based cancer registry. The data were analyzed using the Cox proportional hazards model.

RESULTS

The age-adjusted relative risks (RR) and 95% confidence intervals (CI) of smoking-related cancers and lung cancer for women who had smoking husbands, compared with women whose husbands did not smoke, were 1.7 (0.94 2.9, p = 0.079) and 1.9 (0.81-4.4, p = 0.14), respectively. In contrast, a significant inverse association was observed for breast cancer, the RR (95% CI) was 0.58 (0.34-0.99, p = 0.047). After multivariate adjustment for confounding factors, the risks of smoking-related cancers and breast cancer were materially unchanged.

CONCLUSIONS

These results show that passive smoking may affect the risk of cancers other than lung cancer.

Antisense inhibition of a BRI1 receptor reveals additional protein kinase signaling components downstream to the perception of brassinosteroids in rice

Plants express a variety of proteins at the cell surface responsible for the transduction of regulatory information into the cell via receptors. In the present study, an attempt has been made to identify the components of the brassinosteroids (BRs) signaling transduction cascades in transgenic rice (Oryza sativa) expressing the antisense strand of OsBRI1 transcript. A 60 kDa protein, immunologically characterized as mitogen-activated protein kinase (MAPK), showed reduced phosphorylation activity in the membrane fractions of the OsBRI1 antisense rice over control, demonstrating the inhibition in the perception of BRs by the BRI1 receptor, when compared with the exogenously applied brassinolide. The phosphorylation activity of the 50 kDa Ca(2+)-dependent protein kinase was however increased in the cytosolic fractions of OsBRI1 antisense over control. The data obtained suggest that MAPK and Ca(2+)-dependent protein kinase in rice are discrete but parallel signaling cascades and might involve receptors other than BRI1 in response to BR stimulus.

Passive smoking at home and cancer risk: a population-based prospective study in Japanese nonsmoking women

OBJECTIVES

To investigate the relationship between passive smoking at home and the incidence of various cancers in a population-based prospective study.

METHODS

The subjects were 9675 Japanese lifelong nonsmoking women aged over 40 years who lived in three municipalities of Miyagi Prefecture, and completed a self-administration questionnaire in 1984. During 9 years of follow-up, 426 cancers were identified by record linkage to the population-based cancer registry. The data were analyzed using the Cox proportional hazards model.

RESULTS

The age-adjusted relative risks (RR) and 95% confidence intervals (CI) of smoking-related cancers and lung cancer for women who had smoking husbands, compared with women whose husbands did not smoke, were 1.7 (0.94 2.9, p = 0.079) and 1.9 (0.81-4.4, p = 0.14), respectively. In contrast, a significant inverse association was observed for breast cancer, the RR (95% CI) was 0.58 (0.34-0.99, p = 0.047). After multivariate adjustment for confounding factors, the risks of smoking-related cancers and breast cancer were materially unchanged.

CONCLUSIONS

These results show that passive smoking may affect the risk of cancers other than lung cancer.

Characterization of a Ca2+-dependent protein kinase from rice root: differential response to cold and regulation by abscisic acid

The Ca2+-dependent protein kinases (CDPKs) and abscisic acid (ABA) are known to be involved in low-temperature stress response. The focus of this study was to characterize the 45 kDa protein kinase identified in the crude extract of rice (Oryza sativa L.) seedling roots in response to cold (5 degrees C) stress. The activity of the 45 kDa protein kinase decreased at low temperature as evident by an in-gel kinase assay using histone III-S as a substrate. Also, the Ca2+-dependent activity of this protein kinase was suppressed by cold in the membrane fractions of the root. A general protein kinase inhibitor and Ca2+ chelator inhibited the activity of the 45 kDa protein kinase, suggesting that it was a plant CDPK. The 45 kDa CDPK identified was found to be independent of photosynthetic tissues such as the leaf and leaf sheath of rice seedlings, supporting a direct sensing mechanism in the roots of rice seedlings to cold stress. The suppressed activity of the 45 kDa CDPK was reverted by supplementing with 5 microM ABA under cold stress. The 45 kDa CDPK activity was stronger in the cold-tolerant variety of the 4 types tested than it was in the cold-sensitive one. These results suggest the involvement of endogenous ABA in regulating the activity of the 45 kDa CDPK in response to cold stress.

Monocyte CD14 changes and endotoxemia after major hepatectomy

BACKGROUND/AIMS

This study was designed to ascertain whether decreases in membrane CD14 (mCD14), the endotoxin receptor on the surface of the monocyte cell membrane, reflect the presence of endotoxemia, and whether endogenous endotoxemia is present after hepatectomy.

METHODOLOGY

First, in cases with a definitive clinical diagnosis of endotoxemia, we determined the serum endotoxin level by the ES (Endospesy) method, from the percentage of cells positive for membrane CD14, from the CD14 fluorescence intensity (MFI-CD14), and from the quantification of soluble CD14 (sCD14); and calculated the diagnostic accuracy obtained with each. Next, in 13 cases of extended hepatectomy (in excess of lobectomy) the mCD14-positive rates were determined around the time of the operation, and compared with the clinical courses of infection foci, if any, and other findings.

RESULTS

The diagnostic accuracy of endotoxemia obtained by ES, mCD14, MFI-CD14 and sCD14 were 77.3%, 95.5%, 86.7% and 66.7%, respectively, so that the highest was given by the positive mCD14 cell rate. Although no infectious complication was detected in any of the 9 patients in whom the mCD14-positive rates changed within the normal range, of the 4 patients in whom the mCD14-positive rates fell, 2 had cholangitis due to gram-negative bacilli, one who was infected by central vein catheterization, was thought to have exogenous endotoxemia; and the fourth, in whom no clear focus of infection was detected, ran a temperature of 38 degrees C (over 100 degrees F) of unknown origin for 16 days. In this last patient, gram-negative bacilli were detected in both the saliva and the gastric juice, and so endogenous endotoxemia was suspected.

CONCLUSIONS

These results show that decrease in the mCD14-positive rate is more accurately diagnostic of endotoxemia than the endotoxin value obtained by the ES method, and was considered to be a definitive diagnosis of endotoxemia. In addition, from the reduction of the mCD14-positive rate after extended hepatectomy, it was considered that endogenous endotoxemia occurred in one case out of 13 (8%).

Dynamic expression and essential functions of Hes7 in somite segmentation

The basic helix-loop-helix (bHLH) gene Hes7, a putative Notch effector, encodes a transcriptional repressor. Here, we found that Hes7 expression oscillates in 2-h cycles in the presomitic mesoderm (PSM). In Hes7-null mice, somites are not properly segmented and their anterior-posterior polarity is disrupted. As a result, the somite derivatives such as vertebrae and ribs are severely disorganized. Although expression of Notch and its ligands is not affected significantly, the oscillator and Notch modulator lunatic fringe is expressed continuously throughout the mutant PSM. These results indicate that Hes7 controls the cyclic expression of lunatic fringe and is essential for coordinated somite segmentation.

A proteomics approach towards understanding blast fungus infection of rice grown under different levels of nitrogen fertilization

Proteins extracted from leaf blades of rice plants infected with blast fungus, Magnaporthe grisea, were separated by two-dimensional polyacrylamide gel electrophoresis. The separated proteins were electroblotted onto a polyvinylidene difluoride membrane, and 63 proteins were analyzed by a gas-phase protein sequencer. The N-terminal amino acid sequences of 33 out of 63 proteins were determined in this manner. N-terminal regions of the remaining proteins could not be sequenced. The internal amino acid sequences of 12 proteins were determined by sequence analysis of peptides obtained by the Cleveland peptide mapping method. The amino acid sequences were compared with those of known plant and animal protein sequences to understand the nature of these proteins. As expected, leaf blades revealed predominantly the presence of photosynthetic proteins. Using this experimental approach named as proteome analysis, the functional proteins during blast fungus infection of rice with different levels of nitrogen nutrient were analyzed. Twelve proteins which appeared to change with different levels of nitrogen nutrient were identified. It was revealed that the level of ribulose-1,5-bisphosphate carboxylase/oxygenase was increased by top-dressing with nitrogen nutrient. Additionally, the pathogenesis related protein were observed following blast fungus infection using immunoblot analysis. It was conjectured that these proteins might be involved in incompatible interaction in rice plants following blast fungus infection. The information obtained on the amino acid sequences and antibodies interaction is expected to be helpful in predicting the function of these proteins.

The tip of the coiled-coil rod determines the filament formation of smooth muscle and nonmuscle myosin

Myosin II self-assembles to form thick filaments that are attributed to its long coiled-coil tail domain. The present study has determined a region critical for filament formation of vertebrate smooth muscle and nonmuscle myosin II. A monoclonal antibody recognizing the 28 residues from the C-terminal end of the coiled-coil domain of smooth muscle myosin II completely inhibited filament formation, whereas other antibodies recognizing other parts of the coiled-coil did not. To determine the importance of this region in the filament assembly in vivo, green fluorescent protein (GFP)-tagged smooth muscle myosin was expressed in COS-7 cells, and the filamentous localization of the GFP signal was monitored by fluorescence microscopy. Wild type GFP-tagged smooth muscle myosin colocalized with F-actin during interphase and was also recruited into the contractile ring during cytokinesis. Myosin with the nonhelical tail piece deleted showed similar behavior, whereas deletion of the 28 residues at the C-terminal end of the coiled-coil domain abolished this localization. Deletion of the corresponding region of GFP-tagged nonmuscle myosin IIA also abolished this localization. We conclude that the C-terminal end of the coiled-coil domain, but not the nonhelical tail piece, of myosin II is critical for myosin filament formation both in vitro and in vivo.

Effect of cicletanine on the nitric oxide pathway in human umbilical vein endothelial cells

The purpose of this study was to evaluate the effects of cicletanine, a slightly diuretic antihypertensive drug, on human vascular endothelial cells with regard to nitric oxide, intracellular calcium concentration ([Ca2+]i), cyclic nucleotide, inositol 1,4,5-trisphosphate (IP3), and prostacyclin generation. Primary cultured human umbilical vein endothelial cells were used in this study. [Ca2+]i was measured by fura-2/AM. Cyclic adenosine monophosphate (AMP), cyclic guanosine monophosphate (GMP), IP3, and prostacyclin were measured by radioimmunoassay. Nitric oxide was measured by the Griess method. Cicletanine had no effect on [Ca2+]i. Cicletanine (10(-6)-10(-4) M) increased cyclic GMP but decreased prostacyclin generation. Cicletanine had no stimulating effect on cyclic AMP or IP3 generation. IP3 increased 45Ca release from storage sites. Cicletanine decreased prostacyclin generation via increase in cyclic GMP. Cicletanine had no stimulating effect on nitrogen oxides for 2 h after incubation but increased it after 3-24 h. Pretreatment with L-N(G)-monomethyl-arginine (L-NMMA) prevented this increase. The inhibitory effect of L-NMMA was prevented by pretreatment with L-arginine. These results indicate that nitric oxide and cyclic GMP may contribute to the antihypertensive action of cicletanine.

Expression of p53 tumor suppressor gene in adenoid cystic and mucoepidermoid carcinomas of the salivary glands

Seventeen adenoid cystic carcinomas (ACCs) and 27 mucoepidermoid carcinomas (MECs) occurring in the salivary glands were analyzed for p53 tumor suppressor gene alteration (exons 5-8) and protein expression. The cell proliferation activity was also examined by Ki-67 immunohistochemistry. The p53 alterations were detected in three samples (17.6%) of ACC and in four samples (14.8%) of MEC, and were only found in carcinomas arising in the minor salivary glands. The occurrence of the p53 gene alteration is less frequent in ACC and MEC than that in other kinds of tumors, and therefore does not seem to play a critical role in the course of the tumorigenesis in ACC and MEC. All ACC samples arising from the minor salivary glands exhibiting p53 gene alterations showed recurrence/metastasis, thus suggesting a poor outcome of these patients. All ACCs and three out of four MECs samples with p53 gene alterations showed the lowest degree of p53 immunostaining ratio, thus suggesting that no correlation exists between the p53 gene alterations and the p53 immunostaining in these salivary gland carcinomas. No significant relationship was demonstrated between the immunostaining ratio of either p53 or Ki-67 and the morphological growth pattern or patient clinical course in the ACC samples. The p53 immunopositivity in MEC correlated to the histological grade. The Ki-67 immunostaining ratio was also significantly related to the histological grade and the clinical course in MEC.

Green tea and the risk of gastric cancer in Japan

BACKGROUND

Although laboratory experiments and case-control studies have suggested that the consumption of green tea provides protection against gastric cancer, few prospective studies have been performed.

METHODS

In January 1984, a total of 26,311 residents in three municipalities of Miyagi Prefecture, in northern Japan (11,902 men and 14,409 women 40 years of age or older), completed a self-administered questionnaire that included questions about the frequency of consumption of green tea. During 199,748 person-years of follow-up, through December 1992, we identified 419 cases of gastric cancer (in 296 men and 123 women). We used Cox regression to estimate the relative risk of gastric cancer according to the consumption of green tea.

RESULTS

Green-tea consumption was not associated with the risk of gastric cancer. After adjustment for sex, age, presence or absence of a history of peptic ulcer smoking status, alcohol consumption, other dietary elements, and type of health insurance, the relative risks associated with drinking one or two, three or four, and five or more cups of green tea per day, as compared with less than one cup per day, were 1.1 (95 percent confidence interval, 0.8 to 1.6), 1.0 (95 percent confidence interval, 0.7 to 1.4), and 1.2 (95 percent confidence interval, 0.9 to 1.6), respectively (P for trend=0.13). The results were similar after the 117 cases of gastric cancer that were diagnosed in the first three years of follow-up had been excluded, with respective relative risks of 1.2 (95 percent confidence interval, 0.8 to 1.8) 1.0 (95 percent confidence interval, 0.7 to 1.5), and 1.4 (95 percent confidence interval, 1.0 to 1.9) (P for trend=0.07).

CONCLUSIONS

In a population-based, prospective cohort study in Japan, we found no association between green-tea consumption and the risk of gastric cancer.

Identification of a novel member of the snail/Gfi-1 repressor family, mlt 1, which is methylated and silenced in liver tumors of SV40 T antigen transgenic mice

DNA methylation is the only known mechanism for an epigenetic genomic DNA modification that is capable of altering gene expression. A recent study reveals that the pattern of CpG island methylation is largely characteristic of tumor type, suggesting that distinct sets of genes are inactivated by methylation during development of each tumor type. We compared previously the methylation status between normal liver and liver tumors in SV40 T/t antigen transgenic mice (MT-D2 mice) using Restriction Landmark Genomic Scanning for Methylation (RLGS-M) and identified several loci/spots that appeared to be methylated frequently in liver tumors. One of these spots, B236, identified a locus on chromosome 12 (D12Ncvs7) syntenic with human 14q12-q21 that is frequently lost in certain human cancers. Shotgun sequencing of a bacterial artificial chro mosome clone containing this spot/locus was performed to identify genes within this region. The Genescan program predicted an open reading frame of a novel, intron-less gene adjacent to the B236 spot that encodes a putative 493-amino acid protein containing the SNAG repressor motif in the NH2-terminal region and five C2H2-type zinc finger motifs in the COOH-terminal half. This putative gene, methylated in liver tumor (mlt 1), is a novel member of the SNAG transcriptional repressor family with 43% amino acid identity to insulinoma-associated protein 1. An open reading frame encoding a protein quite similar to mouse mlt 1 (56% amino acid identity) was located in the syntenic region of the human genome, indi cating that mlt 1 is evolutionarily conserved in human. Northern blot analysis revealed that mlt 1 is normally expressed in brain, spleen, stom ach, and liver. However, mlt 1 expression was silenced in the liver tumors of MT-D2 mice. The putative promoter region of mlt 1 is unmethylated in normal tissues but methylated in all liver tumors from 11 MT-D2 mice We also found that mlt 1 was methylated and not expressed in N18TG-22 cells, a mouse neuroblastoma cell line. Treatment of N18TG-2 cells with a demethylating agent, 5-aza-deoxycytidine, resulted in an expression of mlt 1, indicating that the repression of mlt 1 is attributable to methylation Thus, mlt 1 is a novel target gene that is silenced by methylation during liver tumorigenesis initiated by SV40 T antigen.

Prenatal exposure to ethanol induces leptomeningeal heterotopia in the cerebral cortex of the rat fetus

Pregnant rats were fed an ethanol-containing liquid diet between gestational day (GD) 10 and GD 21. Leptomeningeal heterotopias were observed in the cerebral cortex of ethanol-exposed fetuses. They appeared on the brain surface of the lateral cortical region near the rhinal fissure, and were found more numerously in the rostral than the caudal region. These abnormalities contained certain neuronal perikarya, microtubule-associated protein (MAP) 1b-positive neuronal processes, and Rat-401-positive radial glial fibers. Immunostaining for Rat-401 revealed that the heterotopias protruded through breaches in the glia limitans. In adult rats exposed to ethanol prenatally, the heterotopias persisted in the lateral cortical region. We conclude that prenatal exposure to ethanol might induce defects in the glia limitans, resulting in the genesis of leptomeningeal heterotopias. These abnormalities may be related to mental retardation or the cognitive deficits associated with human fetal alcohol syndrome (FAS).

Characterization of the promoter of the murine mac25 gene

It is important to know the regulation of the expression of the mac25 gene because of its reduced expression in several cancer cells and of its induction by some hormonal factors. We cloned the promoter region of the murine mac25 gene and found five repeats of CCAAT sequences, four Sp1 sites, a TATA-like sequence, and an initiator (INR) sequence. Analysis using luciferase reporter plasmids indicated that CCAAT repeats have a strong enhancer activity and the second to fourth Sp1 sites are essential for basal activity of the expression of the mac25 gene. The 1 kb region that contains the promoter and exon 1 of the mac25 gene was in a typical CpG island. As hypermethylation and reduced expression of the mac25 gene were reported in murine liver tumors, methylation of this CpG island may be directly associated with the expression of the mac25 gene and tumorigenesis.