Intragenic deletion in the gene encoding ubiquitin carboxy-terminal hydrolase in gad mice.

The gracile axonal dystrophy (gad) mouse is an autosomal recessive mutant that shows sensory ataxia at an early stage, followed by motor ataxia at a later stage. Pathologically, the mutant is characterized by 'dying-back' type axonal degeneration and formation of spheroid bodies in nerve terminals. Recent pathological observations have associated brain ageing and neurodegenerative diseases with progressive accumulation of ubiquitinated protein conjugates. In gad mice, accumulation of amyloid beta-protein and ubiquitin-positive deposits occur retrogradely along the sensory and motor nervous systems. We previously reported that the gad mutation was transmitted by a gene on chromosome 5 (refs 10,11). Here we find that the gad mutation is caused by an in-frame deletion including exons 7 and 8 of Uchl1, encoding the ubiquitin carboxy-terminal hydrolase (UCH) isozyme (Uch-l1) selectively expressed in the nervous system and testis. The gad allele encodes a truncated Uch-l1 lacking a segment of 42 amino acids containing a catalytic residue. As Uch-l1 is thought to stimulate protein degradation by generating free monomeric ubiquitin, the gad mutation appears to affect protein turnover. Our data suggest that altered function of the ubiquitin system directly causes neurodegeneration. The gad mouse provides a useful model for investigating human neurodegenerative disorders.

Existence of Pink1 antisense RNAs in mouse and their localization.

PTEN-induced kinase 1 (PINK1), which is identified as the gene transactivated by the tumor suppressor PTEN, has been found to be one of the causative genes in Parkinson's disease (PD). In order to understand PD, rodent models containing affected Pink1 such as loss-of-function mutations have been exploited. Recently, natural antisense RNA of PINK1 has been demonstrated to be involved in the regulation of the PINK1 locus. However, no antisense RNAs of Pink1 except for human have been reported so far. Therefore, in the present study, while searching for the Pink1 antisense RNAs in mouse, we found that the antisense RNAs are transcribed from a mouse genomic region corresponding to the human region from which the antisense RNAs are produced. Further, we investigated the localization of the antisense RNAs in mouse brain using in situ hybridization; this demonstrated that the antisense RNAs were localized in the regions of brain where the Pink1 mRNA was found. In addition, the mRNA and antisense RNAs were found more densely in the hippocampus than in the other brain regions in newborn and 1-week-old mice, while those RNAs were found uniformly in the mouse brain regions of embryo day (E) 14, E17, and 8-weeks-old.

Localization of sense and antisense transcripts of Prdx2 gene in mouse tissues.

Recently, it has been reported that antisense RNAs are transcribed from a large number of genes in various species including human and mouse. The Prdx2 gene, which is indicated to be involved in signal transduction related to platelet-derived growth factor as well as to protection from oxidizing agents, has been shown to produce sense and antisense transcripts. To obtain clues for possible roles of Prdx2 antisense transcripts, we have performed Northern blot analysis and in situ hybridization on tissues of 8-week-old C57BL/6J mice. The Northern blot analysis revealed that major parts of sense and antisense transcripts were poly(A-)-RNA. The analysis of the fractionated RNA of fibroblasts indicated that the poly(A-)-RNA would be localized in the cytoplasm of cells. The in situ hybridization demonstrated that the sense and antisense transcripts were localized in almost the same limited areas of brain, testis, and spleen. It also revealed that the sense and antisense transcripts coexisted in Purkinje cells. In thymus and stomach, the antisense transcripts were detected, but sense transcripts were not. When tissues of BALB/c mice were examined by in situ hybridization, the observations were essentially the same as those of C57BL/6J except that it appeared that the amounts of sense and antisense transcripts in testis of BALB/c were greater than those in C57BL/6J, and that the amounts of antisense transcripts in stomach of BALB/c were much smaller than those in C57BL/6J.

Plasmid maintenance functions encoded on Dictyostelium discoideum nuclear plasmid Ddp1.

All of the plasmid-carried genes expressed during vegetative growth are essential for long-term maintenance of plasmid Ddp1 in the nucleus of Dictyostelium discoideum. Deletion of Ddp1 genes expressed only during development had no detectable effect on plasmid maintenance. Deletion of vegetatively expressed genes, either singly or in pairs, resulted in (i) a rapid loss of plasmid from cells grown in the absence of selection for plasmid retention, (ii) variation in the proportion of monomer to multimer forms of the plasmid molecules, and/or (iii) abnormalities in plasmid copy number. At least two plasmid-encoded gene products influence patterns of expression of plasmid genes.

Ornithine decarboxylase overexpression in mouse 10T1/2 fibroblasts: cellular transformation and invasion.

BACKGROUND: Ornithine decarboxylase (ODC) plays a pivotal role in the synthesis of polyamines, a group of chemical compounds that are essential for cell growth. Recent reports have shown that ODC overexpression may be involved in malignant transformation of immortalized NIH 3T3 cells. We have demonstrated that ODC-overproducing mouse breast cancer cells are more invasive in vitro than control cells. However, little information is available concerning the relationship between ODC overexpression, tumor invasion, and metastasis and the signal transduction pathways involved in ODC-induced transformation and invasion. PURPOSE: Our purpose was twofold: 1) to determine whether ODC overexpression is directly involved in tumor cell invasion and 2) to determine whether ODC overexpression induces mitogen-activated protein (MAP) kinase activities that are associated with cell growth and transformation. METHODS: We transfected C3H clone 8 mouse 10T1/2 fibroblasts with an expression vector that carries a complementary DNA encoding rat ODC. Neomycin-resistant cells that overproduced ODC (4-6.5 times the control levels) were isolated. The transformed phenotype of these cells was determined by assessing colony formation and anchorage-independent growth in soft agar. The invasiveness of the cells was studied by means of an invasion assay that used Matrigel-coated filters in Boyden chambers. The MAP kinase activity of the cells was assayed by an in-gel kinase assay, using myelin basic protein as the substrate. RESULTS: Overexpression of ODC induced not only cell transformation and anchorage-independent growth in soft agar but also invasiveness through a Matrigel-coated filter. The ODC-overproducing transfectants showed enhanced MAP kinase activity that paralleled the magnitude of cell invasiveness. CONCLUSIONS: ODC plays a pivotal role not only in cell transformation but also in cancer cell invasion. ODC overexpression enhanced MAP kinase activity. IMPLICATIONS: Our results demonstrate a connection between the polyamine/ODC and the MAP kinase signal transduction pathways and suggest that MAP kinase may play a pivotal role in ODC-induced cell transformation and invasion.

Dictyostelium discoideum nuclear plasmid Ddp5 is a chimera related to the Ddp1 and Ddp2 plasmid families.

The 14,955-bp Dictyostelium discoideum nuclear plasmid Ddp5 contains six transcribed open reading frames. One of these is related to the rep gene of the Ddp2 plasmid, and the other five are related to genes present on the Ddp1 plasmid. The absence of a homolog of the Ddp1 G1 gene, coupled with the presence of the Ddp2 rep gene homolog and of a 1.6-kb inverted repeat analogous to the inverted repeats on members of the Ddp2 plasmid family, suggests that Ddp5 uses Ddp2-like replication and copy number control mechanisms and that it should be assigned to the Ddp2 plasmid family. Ddp5 carries genes homologous to the D1/D3 and D2 genes of the Ddp1 plasmid as well as the Ddp1 G2/G3/D4, G5/D6, and G6/G4/D5 genes. The products of the Ddp5 G2-like, G5-like, and G6-like genes are likely to be transcription factors regulating the expression of themselves and of the other Ddp5 genes. The D1-like and D2-like genes may confer a selective advantage to plasmid-bearing cells, because they can be deleted from plasmid-based shuttle vectors with no apparent effect on vector maintenance. Updated sequence information for the Ddp1 G5/D6, D1/D3, and D2 genes as well as the Dmp1 and Dmp2 G5-like genes is presented. The locations of introns in the G5-like and D1-like genes of Ddp5 and in the homologous genes of the Ddp1, Dmp1, and Dmp2 plasmids were identified. These introns all have GU at the 5' intron border and AG at the 3' intron border, are short (59 to 71 nucleotides), and are AT-rich. A conserved HHCC domain was identified in the G5 proteins; this is a putative zinc binding domain and may be involved in protein-DNA interaction.

Eos: a novel member of the Ikaros gene family expressed predominantly in the developing nervous system.

We identified a novel member of the Ikaros gene family, which has critical roles in the development of lymphoid lineages. This gene, which we named Eos, was expressed predominantly in the developing central and peripheral nervous system. Eos protein could interact with itself and Ikaros protein through its C-terminal portion in the yeast two hybrid assay. These findings suggested that Eos may have important roles in neural development similarly to the Ikaros family in the development of hemolymphoid tissue.

Effect of skim milk and yogurt on serum lipids and development of sudanophilic lesions in cholesterol-fed rabbits.

Three groups of male Japanese rabbits weighing about 2.7 kg each were given experimental diets consisting of high cholesterol food and fluid skim milk, yogurt, or water, and were bled every 4 wk to measure serum lipids. After 12 wk they were killed and concentrations of total cholesterol and atheromatous areas dyed with Oil Red O were determined in the aorta to evaluate the development of atherosclerosis. At 8 and 12 wk, the skim milk group showed significantly lower levels of serum total cholesterol, low-density lipoprotein cholesterol, and triglyceride than the control group. Although no significant difference between the yogurt and control groups in the concentration of serum lipids was observed, total cholesterol concentrations in the aorta were significantly lower in both the skim milk and the yogurt groups than in the control group. The atheromatous areas of the skim milk group (38 +/- 34%) were significantly smaller than those of the control group (75 +/- 25%). Significant difference, however, was not found between the yogurt group (51 +/- 22%) and the control group. Concentrations of total cholesterol in the liver did not differ among the three groups. These results suggest that skim milk may have a preventive effect on the development of atherosclerosis.

Speculations on the role of natural antisense transcripts in mammalian X chromosome evolution.

Recent comprehensive transcriptome analyses in mice have revealed tremendous numbers of natural antisense transcripts in a hitherto ignored category of genes in eukaryotes. We discuss the possible biological roles of these transcripts and their relationships with mammalian sex chromosome evolution. Of 60,770 full-length cDNA sequences, as many as 2,500 pairs of sense-antisense transcripts (SATs) with the potential to form RNA duplex via their complementary sequences have been identified. This high number of antisense transcripts indicates their generic roles in gene expression regulation. These SATs are almost evenly distributed along the chromosomes, with the exception of the X chromosome. The rate of occurrence of SATs on the X chromosome is one-third to one-half that on the autosomes, and this under-representation must be related to a property intrinsic to the X chromosome. Here we hypothesize that monoallelically expressed antisense RNA regulates its sense partner, but that this regulatory system cannot operate on the mammalian X chromosome, as the mammalian X chromosome is effectively in a hemizygous state in both sexes. Loss of such regulation may be involved in the evolution of the X chromosome itself.

Identification of a novel gene, OASIS, which encodes for a putative CREB/ATF family transcription factor in the long-term cultured astrocytes and gliotic tissue.

Gliosis is a characteristic response of astrocytes to inflammation and trauma of the central nervous system (CNS). To study the mechanisms underlying gliosis, we performed differential display screening for genes specifically induced in long-term cultured astrocytes used as an in vitro gliosis model. We identified and characterized a gene (named OASIS, for old astrocyte specifically-induced substance) expressed in long-term cultured mouse astrocytes, or 'old astrocytes (OA)'. The OASIS gene encoded a putative transcription factor belonging to the cyclic AMP responsive element binding protein/activating transcription factor (CREB/ATF) gene family, with homology to box B-binding factor-2 (BBF-2), a Drosophila transcription factor. Its expression was developmentally regulated; OASIS mRNA was primarily expressed in the salivary gland and cartilage in the mouse embryo and it was transiently upregulated in the brain during postnatal two weeks. The expression became weaker in the adult brain. We also demonstrated that an expression of the OASIS mRNA was induced in response to the cryo-injury of the mouse cerebral cortex. The distribution pattern of the OASIS-positive cells in the injured cortex was very similar to that of the glial fibrillary acidic protein (GFAP)-positive cells. These results suggest that OASIS protein may play a role in gliotic events.

[Dietary vitamin intake and cancer].

We collected information on dietary intake from 9230 participants aged 40 years old or more by means of self-administered food frequency questionnaire in Fujieda city in order to conduct prospective study to examine the relationship between dietary VA, C and carotene intakes and subsequent risk of cancer in August 1985. To estimate VA, C, and carotene intakes from this questionnaire we multiplied food frequency scores for individual items (25 foods rich in VA, C, and carotene) by the nutrient contents of the standard portion, after adjustments were made for the seasonal availability of some foods.

Primate origin of the CMT1A-REP repeat and analysis of a putative transposon-associated recombinational hotspot.

The CMT1A-REP repeat on chromosome 17p11.2-12 is proposed to mediate misalignment and meiotic unequal crossover leading to a 1.5 Mb pair duplication associated with Charcot-Marie-Tooth neuropathy type 1A (CMT1A) and a reciprocal deletion associated with hereditary neuropathy with liability to pressure palsies (HNPP). Restriction enzyme endonuclease mapping indicated that the size of the CMT1A-REP repeat is approximately 24 kb and DNA sequence analysis determined that the repeat is flanked by inverted Alu sequences. Full length Alu sequences are present at the centromeric ends of the proximal and distal CMT1A-REP repeats and at the telomeric end of the distal repeat. A truncated Alu sequence is present at the telomeric end of the proximal repeat suggesting that the distal CMT1A-REP repeat is the progenitor copy. The crossover breakpoints for a series of unrelated CMT1A and HNPP patients were mapped using a variant SacI site found only in the proximal CMT1A-REP repeat. Seventy-six percent (66/85) of patients had breakpoints which mapped to a 3.2 kb interval, providing further evidence for a recombinational hotspot within the CMT1A-REP repeat. A mariner-like element was mapped within the CMT1A-REP repeat approximately 700 bp centromeric to the 3.2 kb interval containing the hotspot. Analysis of this sequence suggested that it does not encode a functional transposon. By Northern blot analysis a cloned fragment from the CMT1A-REP repeat containing the mariner-like sequence detected a 2.2 kb transcript only in testis. Two cDNA clones which contain the mariner-like element were isolated from a human testis cDNA library. These clones which are interrupted by Alu and other repeats appear to be non-functional versions of the transposon. The functional relationship of the mariner-like element to the recombinational hotspot remains unknown. The origin of the CMT1A-REP repeat was investigated through an analysis of homologous sequences in non-human primates. Southern blot analysis indicated that the chimpanzee has two copies of a CMT1A-REP-like sequence, whereas gorilla, orangutan, and gibbon have a single copy. A high degree of conservation amongst non-human primates for restriction fragments specific to the human distal CMT1A-REP repeat provides further evidence that the distal repeat is the progenitor copy. The mariner-like sequence was detected in association with the CMT1A-REP sequence in all primates studied suggesting that the mariner-like element was introduced into the progenitor CMT1A-REP sequence prior to emergence of the proximal and distal CMT1A-REP repeats. These observations suggest that CMT1A-REP sequence appeared as a repeat before the divergence of chimpanzee and human, but after gorilla and human around 6 to 7 million years ago.

Case-control study of ovarian cancer in Japan.

A case-control study of 80 women with ovarian epithelial carcinoma and 160 individually age-matched controls were conducted to assess various factors associated with the incidence of ovarian cancer in Hokkaido, Japan. Among the characteristics studied, the following factors were significantly greater in the cases than in the controls: (1) blood group A; (2) never married or married late in life; (3) more frequent surgery for retroflexion of the uterus; (4) less use of contraceptive appliances; and (5) less daily use of cosmetics. It was inferred from these observations that ovarian cancer patients had a genetic predisposition and dysfunctional ovaries. Gonadal dysfunction among ovarian cancer patients presumably explained not only altered personality and behavior patterns, but also facilitated the pituitary gonadotropin activity which has been suggested as increasing the incidence of the disease experimentally.

Compatible Dictyostelium mucoroides nuclear plasmids Dmp1 and Dmp2 both belong to the Ddp1 plasmid family.

Dictyostelium mucoroides plasmids Dmp1 and Dmp2 are naturally occurring compatible members of the Dictyostelium Ddp1 plasmid family found in the same wild isolate strain. The nucleotide sequences of Dmp1 (5983 bp) and Dmp2 (6018 bp) are 74% identical and each carries open reading frames (ORFs) similar to the G1 and G5 ORFs of the Dictyostelium discoideum plasmid Ddp1. The predicted protein product of the Ddp1 G1 ORF is 49% similar to that of the Dmp1 G1-like ORF and 52% similar to that of the Dmp2 G1-like ORF. For the G5 and G5-like ORFs the corresponding values are 47 and 43%, respectively. The G1 and G5 ORFs of Ddp1 are transcribed during both vegetative growth and development of the asexual fruiting body. The G1-like ORF of Dmp2 is expressed in vegetative and developing cells, while that of Dmp1 appears to be expressed mostly in developing cells. The G5-like ORFs of Dmp1 and Dmp2 are expressed in both vegetative and developing cells. Dmp1 and Dmp2 differ from Ddp1 in (1) lacking homologs for the Ddp1 G2/G3/D4, G4/D5, D1/D3, and D2 ORFs; (2) containing multiple copies of a 173 bp direct repeat; and (3) having a different orientation of the G1 ORF relative to the G5 ORF. These findings suggest that the basic replicon unit of the Ddp1 plasmid family is composed of an origin of replication coupled to G1-like and G5-like genes. The additional ORFs and direct repeat elements in Ddp1, Dmp1, and Dmp2 may provide accessory functions beneficial to plasmid maintenance. Shuttle vectors based on Dmp1 or Dmp2 replicate in D. discoideum transformants.

Expression of a sonic hedgehog signal transducer, hedgehog-interacting protein, by human basal cell carcinoma.

BACKGROUND: Aberrant activation of the hedgehog pathway has been identified in various human tumours, including familial and sporadic basal cell carcinomas (BCCs). It has been postulated that binding of sonic hedgehog protein (SHH) to its receptor, patched protein (PTC), releases the inhibitory effect of PTC against smoothened protein (SMO), another protein of the SHH signalling pathway. The positive SMO signalling is not downregulated in BCCs because of the mutational inactivation of PTC. Recently, hedgehog-interacting protein (HIP) was found to bind to SHH directly and attenuate SHH signalling like PTC, while its expression was induced by SHH signals. OBJECTIVES: To examine the expression patterns of HIP, SHH and PTC gene mRNA by human BCCs, in comparison with those by normal human skin and various skin tumours. METHODS: We performed quantitative reverse transcriptase-polymerase chain reaction analyses with a series of samples from BCCs, other skin tumours and normal skin. RESULTS: We found that the mRNA expression of both HIP and PTC genes was enhanced in all samples of BCCs, whereas none of the other skin tumours tested exhibited an increased level of such mRNAs as compared with normal skin. The transcription of the SHH gene, however, was at a baseline level in most BCCs. CONCLUSIONS: These results indicate that both HIP and PTC gene expression are specifically involved in the development of BCCs, and that the production of HIP is linked with the expression of the PTC gene but not the SHH gene.

Decrease of serum triglyceride in normal rats fed with 2000 ppm aluminum diet for 67 days. I. Feeding young rats sucrose, lactose, milk, casein or soy-protein diets with addition of aluminum chloride.

Aluminum (Al) compounds are widely used in drugs and food additives but the toxicity of such compounds is not known in detail except in patients with renal insufficiency (J. W. Coburn and A. C. Alfrey, 1986, Kidney Int. 29, Suppl. 18). In this experiment, toxicity of ingested Al was investigated in relation to nutritional conditions in normal rats having no renal insufficiency. Sucrose, lactose, milk, casein and soy-protein diets were prepared. As the Al source, aluminum chloride (AlCl3) was added to these diets at the level of 2000 micrograms/g (ppm). Male weanling Wistar rats were fed for 67 days without any Al effect on body weight gain. After a half-day starvation they were terminated. The significance of difference resulting from Al treatment was statistically tested between rats consuming diet with or without added Al. Serum Al concentrations did not exceed 20 ng/ml in any of the groups. Tibia Al concentration doubled in rats consuming added Al in every diet but lactose. Liver Al concentration increased significantly in the Sucrose, Milk, and Casein groups compared to each Control group consuming diet without addition of Al. No lactose effect on Al accumulation was observed. With Al treatment, anemia and hypophosphatemia were not observed, but a decrease in tibia weight was observed with every diet. Aluminum-dependent decreases in serum triglyceride (TG) concentration were also observed in all dietary groups, without any effect on serum cholesterol or phospholipid (P-lipid) concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)

Decrease of serum triglyceride in normal rat fed with 2000 ppm aluminum diet for 67 days. II. Feeding young and adult rats a sucrose diet with addition of aluminum hydroxide and aluminum potassium sulfate.

To confirm the hypotriglyceridemic effect of aluminum (Al), male weanling and adult Wistar rats were fed sucrose diets with the addition of aluminum hydroxide (Al(OH)3) or aluminum potassium sulfate (AlK(SO4)2) for 67 days. As in the foregoing report (C. Sugawara, N. Sugawara, H. Kiyosawa, and H. Miyake, Fundam. Appl. Toxicol. 10, 607-615), no Al-induced anemia or hypophosphatemia was observed and serum Al did not exceed 20 ng/ml. Serum triglyceride (TG) was decreased by aluminum. Serum TG was significantly correlated with the serum nonesterified fatty acid (NEFA) concentration in both the Young groups (R = 0.757, n = 22, p less than 0.01) and the Adult groups (R = 0.727, n = 19, p less than 0.01). Neither serum cholesterol nor phospholipids was affected by Al ingestion. Aluminum caused a decrease in hepatic glycogen in all groups, but the decrease was significant only in Adult groups. Glycerol tri[9,10(n)-3H]oleate was administered by gastric tube into rats fed for 81 days with experimental diets. In all the Al-treated groups serum 3H was significantly greater than in control groups at 3 hr after intubation. At 24 hr after intubation, serum 3H did not differ between Control and Al-treated groups. Total 3H at 24 hr found in serum, liver, and epididymal adipose tissue was not changed significantly by Al feeding. These effects were observed without measurable increase of Al in the serum.(ABSTRACT TRUNCATED AT 250 WORDS)

The replication origin position and its relationship to a negative trans-acting transcription regulator encoded by Dictyostelium discoideum nuclear plasmid Ddp1.

The replication origin of the Dictyostelium discoideum plasmid Ddp1 was localized to a 543-bp region. This includes most of the AT-rich intergenic region between the G1 and G5/D6 genes containing both of their promoters and multiple copies of a TTTTGACT repeat. The G5/D6 gene, which lies adjacent to, and partially overlaps, the 543-bp origin region, encodes a trans-acting factor that negatively regulates transcription of the G4/D5 gene. Inactivation of the G5/D6 gene led to expression of a transcript (G6) 0.2 kb larger than the D5 transcript from the G4/D5 gene in vegetative and developing cells. The G5/D6 gene also regulates transcription of the G1, G2/G3/D4 and G5/D6 genes either alone or in concert with other Ddp1 gene products.