Genetics of intracisternal-A-particle-related envelope-encoding proviral elements in mice

Intracisternal-A-particle-related envelope-encoding (IAPE) proviral elements in the mouse genome encode and express an envelope-like protein that may allow transmission of IAPEs as infectious agents. To test IAPE mobility and potential transmission in mice, we have analyzed the distribution of IAPE elements in the genomes of Mus spretus and Mus musculus inbred strains and wild-caught animals. Potential full-length (IAPE-A) proviral elements are present as repetitive copies in DNA from male but not female animals of M. musculus inbred strains and Mus musculus castaneus. Analysis of IAPE-cellular junction fragments indicates that fixation of most IAPEs in the germ line occurred in M. musculus and M. spretus after speciation but before M. musculus inbred strains were derived.

Exclusion of Sox9 as a candidate for the mouse mutant tail-short

The Sry-related gene Sox9 has been proposed as the gene responsible for the mouse skeletal mutant Tail-short (Ts), on the basis of its expression in skeletogenic mesenchymal condensations in the mouse embryo and its chromosomal location in the region of Ts on distal Chromosome (Chr) 11. We present here detailed mapping of Ts locus relative to the Sox9, using an intersubspecific cross. Among 521 backcross progeny, 16 recombinants were detected between Sox9 and Ts, suggesting a separation of 3.5 +/- 0.01 cM, and excluding Sox9 as a candidate for Ts. A further nine recombinants were detected between Ts and the polycomb-like gene M33, suggesting that these loci are separated by 1.8 +/- 0.011 cM. Six microsatellite markers were co-localized to the Ts locus, providing reagents for positional cloning of Ts.

An intrasellar cystic mass and hypopituitarism

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Molecular analysis of a recombinational hotspot adjacent to Lmp2 gene in the mouse MHC: fine location and chromatin structure

Meiotic recombinations in the proximal region of the mouse major histocompatibility complex (MHC) are clustered within certain segments of chromosome, known as hotspots. In this study, we found that one of such hotspots, previously mapped between the Pb and Ob genes, is located very close to the 3' end of the Lmp2 gene, which encodes a subunit of a proteolytic proteasome. To analyze the molecular basis of the site specificity of hotspots, we examined the structure of the chromatin around this Lmp2 hotspot and another one located in the MHC class II Eb gene, by monitoring DNase I-hypersensitive sites (DHSSs) of the chromatin. DHSSs were detected at the both hotspots in the somatic cells. In the meiotic cells, DHSS was detected within the Eb hotspot, as previously reported, but not in the Lmp2 hotspot. Thus, open structure of chromatin during meiosis, as monitored by hypersensitivity to DNase I, is not a general feature of mouse recombinational hotspots, contrasting the case of the lower eukaryote, S. cerevisiae, in which hotspots are always associated with DHSSs.

The presence/absence polymorphism and evolution of the p53 pseudogene in the genus Mus

Distribution of the p53 pseudogene within the house mouse species (genus Mus) was studied with polymerase chain reaction for 37 individuals that were caught at different localities. Pseudogene-specific fragments were detected in some, but not all, individuals of Mus musculus subspecies regardless of locality and type of subspecies. In addition, 3 of 7 individuals belonging to different Mus species carried the pseudogene in their genomes. These results show the existence of an interspecific presence/absence polymorphism of the p53 pseudogene in mice. Sequence analysis of 11 amplified 0.3-kb fragments suggested that the pseudogene originated in an ancestral mouse about 7 million years ago. Thus alleles with and without the p53 pseudogene have persisted through the mice speciation. The evolutionary rate for the p53 functional gene was also estimated to be about 3.3 x 10(-9) per nucleotide site per year.

Selective hypothermic perfusion of canine brain

A method for selective brain cooling by profound hemodilution with cold Ringer's lactate solution was previously reported in 1992. We recently modified this technique by combining it with an ultrafiltration and rewarming circuit between the left jugular vein and the inferior vena cava. We used 12 beagle dogs to study the efficacy of selective cerebral hypothermia induced by this modified technique. The brain temperature decreased to 28 degrees C within 5.4 +/- 2.7 minutes and to 20 degrees C within 15.5 +/- 9.4 minutes. The lowest brain and rectal temperatures were 17.0 +/- 1.8 degrees C and 32.1 +/- 2.2 degrees C, respectively. All animals survived in good condition without evidence of neurological deficits until they were killed at 10 weeks. Histological examination of the brains with 2,3,5-triphenyltetrazolim chloride demonstrated no evidence of ischemic lesions, and even in the hippocampus, there was no evidence of ischemic neuronal damage.

Seroepidemiological survey of lymphocytic choriomeningitis virus in wild house mice in China with particular reference to their subspecies

Serum samples from 337 wild house mice (Mus musculus) from 35 sites in China, collected in 1992 and 1993, were examined for antibodies against lymphocytic choriomeningitis virus (LCMV). Ten samples from eight sites were found to contain such antibodies. Six of the eight positive sites were located in the territory of M. m. gansuensis. One of the other two sites was located in the territory of M. m. castaneus in southern China and the other site was in a habitat of M. m. castaneus which had invaded into the western end of the territory of M. m. homourus. It seems likely that LCMV is distributed in the territories of M. m. gansuensis and M. m. castaneus in China. This is the first report of detection of these antibodies in wild house mice in China and specifically in the territories of M. m. gansuensis and M. m. castaneus.

Variations in ribosomal DNA and mitochondrial DNA among chromosomal species of subterranean mole rats

Restriction site variations in nuclear ribosomal DNA (rDNA) spacers and mitochondrial DNA (mtDNA) were examined in several populations of mole rats with variable numbers of chromosomes, which represented the two superspecies Spalax leucodon (2n = 38, 54, or 62) and Spalax ehrenbergi (2n = 52, 54, 58, or 60). Sequence divergence of rDNA spacers between the members of the superspecies was approximately 8%, while the variation within each superspecies was 4% on average. The intrasuperspecies differentiation of rDNA spacers was generally associated with changes in the diploid number of chromosomes. However, substantial divergence (approximately 1.5%) was also detected among populations with the same diploid number of chromosomes. The sequence divergence of mtDNA among haplotypes of S. ehrenbergi was 10% or higher and among haplotypes of S. leucodon it was approximately 12%. By contrast, the range of sequence divergence between superspecies was 7.4%-12%. The large divergence of mtDNAs within each superspecies of mole rats may be explained by the preservation of ancient mtDNA polymorphisms.

A duplicated zone of polarizing activity in polydactylous mouse mutants

The positional signaling along the anteroposterior axis of the developing vertebrate limb is provided by the zone of polarizing activity (ZPA) located at the posterior margin. Recently, it was established that the Sonic hedgehog (Shh) mediates ZPA activity. Here we report that a new mouse mutant, Recombination induced mutant 4 (Rim4), and two old mutants, Hemimelic extra toes (Hx) and Extra toes (Xt), exhibit mirror-image duplications of the skeletal pattern of the digits. In situ hybridization of the embryos of these mutants revealed ectopic expression of Shh and fibroblast growth factor-4 (Fgf-4) genes at the anterior margin of limb buds. The new mutation, Rim4, was mapped to chromosome 6 with linkage to HoxAbut segregated from HoxA. No linkage to other known polydactylous mutations was detected. In this mutant, ectopic expression of the Hoxd-11 gene, thought to be downstream of ZPA, was also observed at the anterior margin of the limb buds. All results indicate the presence of an additional ZPA at the anterior margin of limb buds in these mutants. Thus, it appears that multiple endogenous genes regulate the spatial localization of the ZPA in the developing mouse limb bud.

Allele-dependent recombination frequency: homology requirement in meiotic recombination at the hot spot in the mouse major histocompatibility complex

Meiotic recombination break joints in the mouse major histocompatibility complex (MHC) are clustered within short segments known as hot spots. We systematically investigated the requirement for sequence homology between two chromosomes for recombination activity at the hot spot next to the Lmp2 gene. The results indicated that a high rate of recombination required a high degree of similarity of overall genome structure at the hot spot. In particular, the same copy number of repetitive sequences within the hot spot was essential for a high frequency of recombination, suggesting that recombination in mouse meiosis is more sensitive to heterozygous deletion or insertion of DNA than to mismatches of single-base substitutions.

Thrombotic thrombocytopenic purpura and myoglobinuric acute renal failure following radiation therapy in a patient with polymyositis and cervical cancer

A 73-year-old woman was admitted to receive radiation treatment for uterine cervical cancer, however a complex series of events ensued, leading to death. She developed an acute exacerbation of polymyositis complicated by thrombotic thrombocytopenic purpura, rhabdomyolysis and acute renal failure. Radiation therapy may have produced an immune disturbance leading to the acute exacerbation of polymyositis. Auto-immune-mediated endothelial damage might have triggered a series of events leading to thrombotic thrombocytopenic purpura. Rhabdomyolysis seemed to be the main cause of acute renal failure.

Hotspots of homologous recombination in mouse meiosis

The molecular mapping of recombinational breakpoints in the proximal region of the mouse MHC has revealed four hotspots at which breakpoints are clustered. A direct comparison of the nucleotide sequences of two independent hotspots revealed common molecular elements: a consensus sequence of the middle-repetitive MT-family, a repeat of tetramer sequences and a sequence homologous to a solitary LTR of mouse retroviruses. Extremely high frequency of recombination is observed at these hotspots when particular MHC haplotypes are used in genetic crosses. Wild mouse-derived wm7 haplotype instigates recombination at the hotspot located at the 3'-end of the Lmp-2 gene only during female meiosis. Fine genetic analysis demonstrated that the wm7 haplotype carries a genetic factor to instigate recombination and another factor to suppress recombination specifically during male meiosis. In addition, there is no dose effect of the hotspot on frequency of recombination. Finally, we described an attempt to establish an efficient in vitro assay system for monitoring recombination using plasmid DNAs that contain the Lmp-2 hotspot and nuclear extracts prepared from mouse testis.

Radiation-induced lymphomas in MSM, (BALB/cHeA x MSM) F1 and (BALB/cHeA x STS/A) F1 hybrid mice

M.MOL-MSM (MSM) mice derived from Mus musculus molossinus progenitors showed extreme resistance to the induction of lymphomas following whole-body X-irradiation with four doses of 1.7 Gy. (BALB/cHeA x MSM) F1 mice between a high lymphoma strain, BALB/cHeA and the MSM showed a high incidence of radiation-induced lymphomas which was quite similar to that in BALB/cHeA mice, but the latent period was prolonged in the hybrids. Susceptibility in incidence was dominant over resistance in these crosses. Incidences of (BALB/cHeA x MSM)F1 hybrids irradiated with four doses of 2.5 Gy X-rays were 77% in females and 88% in males. F1 hybrids between BALB/cHeA and another resistant strain STS/A, (BALB/cHeA x STS/A) F1, also showed a high level of susceptibility, that is, lymphoma incidence was 64% in females and 63% in males. The mean latent period in the (BALB/cHeA x STS/A) F1 hybrids was similar to that in (BALB/cHeA x MSM) F1 hybrids. As all cases of tumors developed in F1 hybrids are informative concerning the detection of the loss of heterozygosity in the loci depending on the combination of two parental strains, the radiation-induced lymphomas obtained from (BALB/cHeA x MSM) F1 and (BALB/cHeA x STS/A) F1 hybrids could be useful for fine analysis of the genetic alterations involved in lymphomagenesis.

Methylation imprinting was observed of mouse mo-2 macrosatellite on the pseudoautosomal region but not on chromosome 9

Mouse mo-2 macrosatellites consisting of 31-bp tandem repeat units are mainly located at two loci in the C57BL/6 genome, one being at the centromere-distal telomeric region of chromosome 9 and the other at the pseudoautosomal (PA) region of chromosomes X and Y. The two clusters constitute approximately 300 kb and 150 kb, respectively. Southern analysis of a methylation-sensitive enzyme, HpaII-digested DNA showed that the mo-2 macrosatellites are detected as more than 30 polymorphic bands. Comparison of those bands between reciprocally crossed F1 mice revealed that approximately 20% of the allele-specific fragments exhibit different band intensities depending on the sex of the parent of origin. The differential methylation is observed in the mo-2 macrosatellite on the PA region but not in that on chromosome 9. Several fragments including the 3.4-kb fragment without internal HpaII site are more clearly detected when paternally derived, suggesting that the male-derived macrosatellite is undermethylated. Interestingly, the difference is much more remarkable in inter-subspecific F1 mice between C57BL/6 and MSM than F1 between C57BL/6 and C3H/He. This suggests the presence of a modifier(s) that affect(s) the methylation of mo-2 in the MSM genome.

Cubital tunnel syndrome in a patient in long-term haemodialysis

The onset mechanism of cubital tunnel syndrome and carpal tunnel syndrome may be similar in haemodialysis patients. Carpal tunnel syndrome is well recognized as a consequence of dialysis-associated amyloidosis. This case report documents the development of cubital tunnel syndrome in a patient on haemodialysis treatment for 10 years. Proliferating granulation tissue at the elbow had entrapped and displaced the ulnar nerve. This was corrected surgically, and the patient experienced immediate relief of the numbness and the "tingling", but the muscular atrophy had not improved after 8 months.

Survival of steroid 21-hydroxylase-deficient mice without endogenous corticosteroids after neonatal treatment and genetic rescue by transgenesis as a model system for treatment of congenital adrenal hyperplasia in humans

The genome of mice with the H-2aw18 haplotype has a deletion of approximately 80 kilobases in the H-2 class III region of chromosome 17. Mice that are homozygous for the mutation die soon after birth. A functional form of steroid 21-hydroxylase (21-OHase) is encoded by the deleted DNA fragment, and H-2aw18 homozygotes are deficient in this enzyme. 21-OHase catalyzes the conversion of progesterone to deoxycorticosterone during adrenal steroidogenesis in mice; therefore, H-2aw18 homozygous mice are unable to synthesize corticosteroids. The deleted region also includes the gene for complement component C4, which has a role in the classical pathway of the complement activation cascade. To clarify the cause of the lethality of the mutation, we first administered either an adrenal homogenate or synthetic steroids to newborn mice; as a result, several H-2aw18 homozygotes were rescued. The results demonstrated that the mutant mice die as the result of a defect in adrenal steroidogenesis. The low efficiency of the rescue by treatment of newborns (16.0% by the adrenal homogenate and 14.8% by the synthetic steroids) suggested that mutant mice should be treated prenatally. Moreover, because the 21-OHase gene is expressed before birth, introduction of a gene for 21-OHase should improve the efficiency of rescue. The results of the murine mutation are similar to those of the inherited human disease known as congenital adrenal hyperplasia, which is caused by steroid 21-hydroxylase deficiency. As a model system for treatment of the human disease by genetic therapy, we used transgenic approaches to introduce a recombinant DNA fragment containing the murine genomic gene for 21-OHase into the mutant mice. We produced four lines of transgenic mice, and in all four transgenic lines, the transgene rescued the lethal mutation. The apparent efficiencies of rescue were 80.2%, 80.0%, 68.7%, and 16.7% for the respective lines of transgenic mice. During the course of our experiments, we also found an unexpected property associated with the role of corticosteroids. The H-2aw18 homozygous mice rescued by neonatal treatment survived for a long period without further treatment. This observation indicates that corticosteroids down-stream of 21-OHase in the pathway for adrenal steroidogenesis are not essential for the survival of mice, except during the period immediately after birth.

Insertional mutation of int protooncogenes in the mammary tumors of a new strain of mice derived from the wild in China: normal- and tumor-tissue-specific expression of int-3 transcripts

A new mouse strain, Mus musculus Jyg, has been isolated from the wild in China. After several generations of inbreeding, Jyg mice have been found to develop mammary adenocarcinomas at a high incidence (70-80%). In order to understand the mechanism by which mammary tumors are induced in these mice, we analyzed 23 available mammary tumors and liver tissues with regard to mouse mammary tumor virus (MMTV) proviral integrations and the pattern of int oncogene (Wnt-1, int-2/Fgf-3, and int-3) rearrangements and expression. We found that (1) Jyg mice do not carry endogenous MMTV; (2) all tumors showed multiple MMTV proviral integrations and expressed high levels of MMTV; (3) Jyg MMTV is distinguishable from other MMTV strains; (4) a high percentage of the tumors (70%) had insertional mutations in int loci (Wnt-1, 26%; int-2, 13%; and int3, 43%); and (5) unlike Wnt-1 and int-2, a 5.9-kb int-3-related transcript is expressed in developing mouse embryos of all stages and adult mouse tissues including mammary tumors, whereas a 2.4- to 3.6-kb transcript is expressed only in Jyg mammary tumors with int-3 mutations. Taken together, this newly developed mouse strain and the milk-borne MMTV that it carries constitute a novel system for studies of the host and viral specificity of insertional mutagenesis of multiple int protooncogenes by MMTV and the role of these genes in the pathogenesis of mouse mammary carcinomas and tumor cell heterogeneity.

Recombination in the class III region of the mouse major histocompatibility complex

The sites of meiotic recombination in the class II region of the mouse major histocompatibility complex (MHC) are clustered at hotspots. To search for hotspots in the class III region, we mapped recombinational breakpoints of 79 Ab:H2-D recombinants with 11 DNA markers; these included Tnx, the gene for an extracellular matrix protein, tenascin X, the Notch-related Int3 gene, and a microsatellite marker, D17Mit13, none of which had previously been mapped precisely. The results gave the gene order of Eb-61.1-Int3-Tnx-Cyp21/C4-Bf-Hsp68c-D17Mit13+ ++-Tnfa/Tnfb-D. The crossover sites in 40 of the 79 recombinants were confined within the Eb/Int3:Tnx/Cyp21 interval. The result demonstrated that an unequal distribution of recombination is a general feature of the mouse MHC, suggesting the presence of a recombinational hotspot within the Int3:Tnx interval.

Structure, function, and evolution of mouse TL genes, nonclassical class I genes of the major histocompatibility complex

In contrast to well-studied "classical" class I genes of the major histocompatibility complex (MHC), the biology of nonclassical class I genes remains largely unexamined. The mouse TL genes constitute one of the best defined systems among nonclassical class I genes in the T region of the MHC. To elucidate the function and the evolution of TL genes and their relationship to classical class I genes, seven TL DNA sequences, including one from a Japanese wild mouse, were examined and compared with those of several mouse and human classical class I genes. The TL genes differ from either classical class I genes or pseudogenes in the extent and pattern of nucleotide substitutions. Natural selection appears to have operated so as to preserve the function of TL, which might have been acquired in an early stage of its evolution. In a putative peptide-binding region encoded by TL genes, the rate of nonsynonymous (amino acid replacing) substitution is considerably lower than that of synonymous substitution. This conservation is completely opposite that in classical class I genes, in which the peptide-binding region has evolved to diversify amino acid sequences so as to recognize a variety of antigens. Thus, it is suggested that the function of TL antigens is distinct from that of classical class I antigens and is related to the recognition of a relatively restricted repertoire of antigens and their presentation to T-cell receptors.

Sequences and evolutionary analysis of mouse 5S rDNAs

We selectively amplified the spacer regions of genes for mouse 5S ribosomal RNA (rRNA), which are tandemly repeated, by the PCR method, using primers specific to the two ends of the coding region for 5S rRNA. Fragments of approximately 1.6 kb were amplified from DNA from the BALB/cCrSlc mouse (Mus musculus domesticus), the SM/J mouse (M. m. domesticus), the MOA mouse (M. m. musculus) and the SEG mouse (M. spretus). These fragments were cloned into an appropriate plasmid vector, and two clones representative of each of the four strains were sequenced. The sequences were GC rich (> 60%) and contained a high proportion of very simple repetitive motifs, such as (TG)n and (ATCC)n, which accounted for the intra- and intergenomic length heterogeneity. Excluding such polymorphic regions and neglecting small insertions or deletions, we estimated the sequence divergence between clones. Sequence divergence within a genome averaged 0.26%, and the divergence between individuals of the same subspecies, between subspecies, and between species was 0.44%, 0.62%, and 1.73%, respectively. The results indicate that the spacer region evolved rapidly but with a reduction in heterogeneity within each genome, as a result of certain, as yet unidentified, homogenization mechanisms. The results further suggest that the spacer regions of genes for 5S rRNA may provide good indicators for phylogenetic analysis of closely related species.

Extradural extension of primitive neuroectodermal tumor--case report

A 13-year-old boy presented with a primitive neuroectodermal tumor (PNET) with unusual extracranial extension. Precontrast computed tomography showed the tumor as a ring-shaped high-density area which was enhanced postcontrast, with a low-density center. Magnetic resonance imaging showed the tumor as a low-intensity area on the T1-weighted images with marked enhancement by gadolinium-diethylenetriaminepentaacetic acid, and high intensity on the T2-weighted images. The central area appeared as high intensity on both images, suggesting free methemoglobin. The tumor was subtotally removed. Histological examination demonstrated PNET. Despite irradiation (20 Gy) to the surgical site, and further tumor removal, he died 6 months later. This case showed PNET can extend extracranially. Diagnosis and treatment of such a tumor located extracranially and intracranially require careful consideration.

The ter primordial germ cell deficiency mutation maps near Grl-1 on mouse chromosome 18

A single recessive gene, ter (teratoma), causes germ cell deficiency and a high incidence of congenital testicular teratomas in the 129/Sv-ter strain of the mouse. Linkage analyses between the ter gene and 36 marker genes of 19 chromosomes were performed with matings between the C57BL/6J-ter congenic strain and four inbred strains. Results showed that the ter gene was linked to D18Mit9, D18Mit14, and D18Mit17 on Chromosome (Chr) 18. Gene order estimated on the basis of recombination distance (in centimorgans) was [centromere-D18Mit14-5.1 (cM)-ter-0 (cM)-D18Mit17-23.8 (cM)-D18Mit9]. D18Mit17 is the microsatellite DNA of the Grl-1 (glucocorticoid receptor-1) locus. We conclude that the ter gene is closely linked to Grl-1 on Chr 18 and is a new mutation involving the developmental modification of primordial germ cells in mice.

Distribution of mouse mammary tumor virus in Asian wild mice

Several groups of wild mice (Mus musculus) were captured from eight different locations in Asia and bred for several generations in a facility free of any laboratory strains of mice carrying mouse mammary tumor virus (MMTV). The distribution of endogenous MMTV proviral sequences in the liver tissues of these mice was investigated by using Southern blot hybridizations. Four categories of mice were identified. Mice originating from Bogor, Indonesia (Cas-Bgr); He-mei, Taiwan (Cas-Hmi/1); and Malaysia (Cas-Mal) were found to carry an endogenous MMTV provirus consisting of the env, gag-pol, and long terminal repeat sequences. Mice captured from Kojuri, Republic of Korea (Sub-Kjr); Nagoya, Japan (Mol-nag); and three Chinese provinces, Shanghai (Sub-Shh), Beijing (Sub-Bjn), and Jiayuguang (Sub-Jyg/1), appeared to carry defective proviruses. Some mice originating from He-mei (Cas-Hmi/2) and Jiayuguang (Sub-Jyg/2) were found to be completely free of endogenous MMTV. Interestingly, however, the Sub-Jyg/2 mice, after several generations of inbreeding, were found, unlike all of the other subspecies that we examined in the present study, to develop mammary tumors at a high incidence (80 to 90%) with a short period of latency. Electron microscopic examination of the mammary glands and mammary tumors of these mice revealed the presence of numerous intracytoplasmic A, immature, budding, and mature B particles. Furthermore, the mammary tumors were found to contain MMTV proviral sequences. It seems, therefore, that Sub-Jyg/2 mice carry an exogenous MMTV which contributes to their developing mammary tumors.

No dosage effect of recombinational hotspots in the mouse major histocompatibility complex

The sites of meiotic recombination in the proximal region of the mouse major histocompatibility complex (MHC) are clustered at hotspots. Some MHC haplotypes derived from Asian wild mice increase the frequency of recombination at such hotspots when heterozygous with standard laboratory haplotypes. The wm7 and cas3 haplotypes have a hotspot close to the Lmp-2 gene (Lmp-2 hotspot), and the cas4 haplotype has a hotspot about 100 kilobase (kb) proximal, close to the Pb gene (Pb hotspot). To examine the effect of a double dose of hotspots, we estimated the rate of recombination and determined the location of the breakpoints in crosses of wm7/cas3 and wm7/cas4. In 3570 backcross progeny we identified 29 new recombinants in the H-2K to Ab interval, at a frequency of 0.81%. This frequency is 40-fold higher than in crosses between laboratory haplotypes and very similar to those previously obtained in crosses between these wild and standard laboratory haplotypes. Thus, a double dose of hotspots has no additive effect on the frequency of meiotic recombination. The site-specificity of recombination was also conserved. Twenty-three breakpoints were confined within 5.4 kb in the Lmp-2 hotspot, and six breakpoints from the cas4 cross were located in the Pb hotspot, which we have now confined to a 15 kb segment.

Chromosomal mapping of mouse 5S rRNA genes by direct R-banding fluorescence in situ hybridization

The mouse 5S rRNA gene was mapped by direct R-banding fluorescence in situ hybridization (FISH) with biotinylated probes. Two genomic fragments amplified by PCR from total genomic DNA of BALB/c mice and Mus spretus, a 0.16-kb fragment that included the 121-bp 5S rRNA gene and a 1.6-kb fragment that included the whole spacer region, were used for chromosomal mapping of the 5S rRNA gene. Both fragments hybridized to a single locus on a pair of autosomal chromosomes of BALB/c mice. The major cluster of mouse 5S rRNA genes was assigned to the most terminal R-negative to R-positive bands of the E region of mouse Chromosome 8, which is homologous to the linkage of the 5S rRNA gene on the long arm of human chromosome 1. The location of the 5S rRNA gene was mapped in five laboratory strains, in wild mice of six Mus musculus subspecies (domesticus, brevirostris, musculus, bactrianus, castaneus, and molossinus) derived from 10 separate localities, and in four different Mus species (spretus, hortulanus, spicilegus, and caroli), using FISH. The 5S rRNA cluster mapped to the same position on the chromosomes of all mouse species and subspecies studied. These results suggest that the location of the mouse 5S rRNA gene on the distal telomeric region of Chromosome 8 is evolutionarily conserved. In comparison, the chromosomal assignments of centromeric 18S-28S rRNA genes are highly variable among the different M. musculus subspecies and Mus species.

Novel mouse microsatellites: primer sequences and chromosomal location

Sixty-nine sequences containing microsatellites were determined by analysis of clones from a pUC118 library of total genomic mouse DNA. These sequences were examined for size variation using polymerase chain reaction and gel electrophoresis. Fifty-one of them showed allelic variations between C57BL/6 and MSM, the two strains used for genetic mapping. Hence, their chromosomal location was determined using a panel consisting of 131 backcross mice that had been typed with 85 anchor loci. The microsatellites were distributed to most chromosomes except for chromosomes 16 and 19. These novel markers with defined locations are useful in linkage and genome mapping studies.

[Anesthetic management of patients with pheochromocytoma for adrenalectomy using balanced anesthesia with continuous infusion of nicardipine and nitroglycerin]

Four patients underwent surgical removal of pheochromocytoma under balanced anesthesia with fentanyl, sevoflurane and epidural anesthesia combined with continuous infusion of nicardipine and nitroglycerin. Circulation was stable during the operation in all the patients. There were no serious hypertension and hypotension, arrhythmia and pulmonary edema during the postoperative period. We conclude that the anesthetic management of patients with pheochromocytoma for adrenalectomy using balanced anesthesia with continuous infusion of nicardipine and nitroglycerin is one of the most useful anesthetic methods.

A variant family of mouse minor satellite located on the centromeric region of chromosome 2

A variant sequence of minor satellite that exhibits a polymorphism in strains and a subspecies of the mouse by pulsed-field gel analysis has been cloned. A segregation study using intrasubspecific backcross mice reveals that the variant maps to the centromeric region of chromosome 2. A long-range physical analysis of the region shows that the variant family is probably located between the proximal telomere and the major satellite. The sequence probe provides an important marker of the chromosome 2-specific centromere.

Clinical significance of TAL1 gene alteration in childhood T-cell acute lymphoblastic leukemia and lymphoma

The TAL1 gene is altered as a consequence of t(1;14)(p32;q11) found in T-cell acute lymphoblastic leukemia (ALL) and shows site specific recombination (tald rearrangement). We investigated TAL1 gene alterations in 39 children with T-cell ALL, in 32 with B-precursor ALL, in three with ALL with myeloid-associated antigen, and in 18 with T-non-Hodgkin's lymphoma (T-NHL). tald rearrangement was found in nine of 39 T-cell ALL patients using Southern blot analysis with a TAL1 gene probe. Polymerase chain reaction (PCR) products predicted from the sequences of the corresponding tald alleles were shown in all of these patients. In contrast, no rearranged band was observed in other kinds of leukemia or in T-NHL patients. All of these patients with tald rearrangement had CD1- CD2+ CD4- CD7+ CD10- pheno-type. Of these, seven were classified as stage I thymic differentiation, and eight have survived for three to 59 months remission. Four of seven patients investigated had normal karyotypes, which has been reported to be associated with a good prognosis in T-cell ALL. We conclude that tald rearrangement is restricted to T-cell ALL, for which it provides a useful clonal marker. Such patients with this rearrangement may constitute a subgroup of T-cell ALL with a good prognosis.

Hotspots of meiotic recombination in the mouse major histocompatibility complex

Meiotic recombination is not random in the proximal region of the mouse major histocompatibility complex (MHC). It is clustered at four restricted positions, so-called hotspots. Some of the MHC haplotypes derived from Asian wild mice enhance recombination at the hotspots in genetic crosses with standard MHC haplotypes of laboratory mouse strains. In particular, the wm7 haplotype derived from Japanese wild mouse indicated an approximately 2% recombination frequency within a 1.2 kb fragment of DNA in the interval between the Pb and Ob genes. Interestingly, this enhancement of recombination was observed only in female meiosis but not in male meiosis. Mating experiments demonstrated that the wm7 haplotype carries a genetic factor in the region proximal to the hotspot, which instigates recombination. In addition, the wm7 haplotype has a genetic factor located in the region distal to the hotspot, which suppresses recombination. From the molecular characterization of the two hotspots located in the Eb gene and the Pb-Ob interval, it appeared that there are several common molecular elements, the consensus of the middle repetitive MT-family, TCTG or CCTG tetramer repeats, and the solitary long terminal repeat (LTR) of mouse retrovirus.

[Primary adenomatous tumor of the middle ear: a case report]

A case of primary adenomatous tumor of the middle ear is described. A 16-year-old male was admitted with a one-year history of left hearing disturbance. Skull X-ray disclosed destruction of the left petrous bone. Computed tomographic scans revealed an iso-dense mass in the left petrous bone, which was slightly enhanced. The tumor appeared as a low intensity mass on T1-weighted magnetic resonance image (MRI) and as high-intensity mass on T2-weighted MRI, and was enhanced by Gd-DTPA. Fluid in the peritumoral area showed high intensity on T1- and T2-weighted MRI. External carotid angiography revealed a marked tumor stain fed by the ascending pharyngeal artery. At operation, the tumor was found to be soft and to bleed easily. Histological diagnosis was adenomatous tumor presenting a papillary pattern. Adenomatous tumor of the middle ear is rare and difficult to classify. Nevertheless, papillary adenomatous tumor of the middle ear could often be aggressive and malignant in behavior and this patient will require long-term follow up. This is the first report to our knowledge of MRI findings about primary adenomatous tumor of the middle ear.

Molecular cloning of the b subunit of mouse coagulation factor XIII and assignment of the gene to chromosome 1: close evolutionary relationship to complement factor H

The b subunit of human coagulation factor XIII (FXIII-b) is composed of 10 short consensus repeats (SCRs) characteristic of the regulatory proteins of complement activation system. A full-length cDNA clone of mouse FXIII-b was isolated and the entire sequence was determined. The predicted amino acid sequence showed 77.5% homology with human FXIII-b, although mouse FXIII-b contained seven extra amino acid residues at the carboxyl terminal. The strong reactivity of the translation product of this clone with rabbit anti-human FXIII-b antiserum confirmed that it encodes a mouse counterpart of the human FXIII-b. By in situ hybridization and mapping studies using 66 interspecific backcross mice, the mouse FXIII-b gene (designated F13b) was shown to be located on distal chromosome 1 closely linked to Cfh, extending a conserved linkage group between human and mouse chromosome 1. In addition, a significant structural similarity between FXIII-b and complement factor H is described.

[Anesthesia for venoplasty of right hepatic vein and liver portion of inferior vena cava using veno-venous bypass]

A patient with Budd-Chiari syndrome who underwent a new surgical technique; venoplasty of right hepatic vein and liver portion of inferior vena cava using veno-venous bypass, was reported. The patient was 31 year-old man whose weight and height were 55 kg and 157 cm, respectively. During the anesthetic management of this patient, we encountered following problems; continuous massive bleeding, profound hypothermia and hemodynamic derangement. These problems were similar to those of liver surgery using veno-venous bypass such as extracorporeal liver surgery and liver transplantation.

Augmented induction by dexamethasone of metallothionein IIa messenger ribonucleic acid in fibroblasts from a patient with cortisol hyperreactive syndrome

Northern blot analysis was used to investigate the effect of dexamethasone (Dex) or zinc on messenger RNA (mRNA) levels of metallothionein-IIa (MT-IIa) in fibroblasts from a patient with cortisol hyperreactive syndrome and from three normal subjects. Dex was seen to increase MT-IIa mRNA levels and brought them to a maximum after 12 h. Zinc also increased the levels of MT-IIa mRNA and brought them to a maximum at 8 h after the addition. Dex as well as zinc caused a dose-related increase in MT-IIa mRNA levels. Dex had a maximal inductive effect on MT-IIa at a concentration of 10(-6) mol/L and zinc at a concentration of 10(-4) mol/L. There was no significant difference in the levels of basal expression of the MT-IIa gene between the patient's and normal fibroblasts. But in three separate experiments induction of MT-IIa gene by Dex obtained for the patient's fibroblasts was almost twice as much as that for normal fibroblasts. On the other hand, there were no significant difference in induction by zinc between the patient's and normal fibroblasts. These data indicated that the patient's cells were hyperreactive to glucocorticoids as seen from the effect of Dex on the MT-IIa mRNA levels.

Aromatase activity in human hepatocellular carcinoma. Relationship with the degree of histologic differentiation

Human hepatocellular carcinomas (HCC) were examined aromatase activity, an enzyme that converts androgen into estrogen. Such activity was detected in all 13 specimens of HCC (mean activity, 120 fmol/30 min/mg microsomal protein). The activity tended to be lower in the HCC tissue than in the surrounding liver tissue (mean activity, 230 fmol/30 min/mg microsomal protein), although it was higher in the HCC tissue from three of eight patients with Edmondson's Grade 2 disease. This relationship was not found in the five with Grade 3 disease. On the whole, aromatase activity was significantly higher in specimens from patients with Edmondson's Grade 2 tumors than in the less differentiated Grade 3 type (P < 0.05). These observations suggested that aromatase activity was present in human HCC and was related to the degree of histologic differentiation.

Mapping of the Mod-1 locus on mouse chromosome 9

A new method for typing the Mod-1 locus on mouse Chromosome (Chr) 9 was developed, based on restriction fragment length polymorphism (RFLP) within a polymerase chain reaction (PCR)-amplified fragment. The new method led us to revise the strain distribution pattern (SDP) of Mod-1 in the BXD (C57BL/6J x DBA/2J) and AKXD (AKR/J x DBA/2J) recombinant inbred (RI) strains. The new SDP eliminates several previously reported examples of double recombination events between Mod-1 and the closest flanking loci in the BXD and AKXD strains. In the BXD strains, the revised SDP of Mod-1 was identical to that of the Mod-1-related D9Rtil locus. Thus, the identity of D9Rtil as a Mod-1-related locus rather than Mod-1 itself is in question. The method was also applied to an interspecific backcross panel between an inbred strain of Mus musculus molossinus (MSM/Ms) and C57BL/6J to map Mod-1 with respect to surrounding microsatellite loci, defining the proximal localization of Mod-1 with respect to D9Mit10 with a genetic distance of 0.6 +/- 0.6 cM.

Actions and interactions of glucocorticoids and transforming growth factor beta on two related human myeloma cell lines

To evaluate possible involvement of a paracrine/autocrine inhibitory growth factor in myeloma cell growth, we studied the expression and actions of two forms of transforming growth factor beta (TGF-beta 1 and TGF-beta 2) on two closely related myeloma cell lines, OPM-1 and OPM-2. Earlier studies showed that both cell lines contain glucocorticoid receptors, but only OPM-2 cells are growth inhibited by dexamethasone (Dex). We found that OPM-2 growth was inhibited by TGF-beta, with TGF-beta 1 exerting a greater effect than TGF-beta 2, and Dex plus TGF-beta 1 acting synergistically. In OPM-1 (Dex insensitive), TGF-beta mRNA was not expressed, whereas it was induced by Dex in OPM-2. It was also possible to block partially the growth inhibition of Dex in OPM-2 cells by the addition of anti-TGF-beta 1 antibodies. These data suggest that the glucocorticoid effect(s) on myeloma cells may be mediated at least in part through modulation of internal and/or external levels of TGF-beta 1.

A new Pax gene, Pax-9, maps to mouse chromosome 12

Members of the Pax gene family have recently been shown to play important roles in mouse embryogenesis. Of eight so far characterized Pax genes, three have been associated with mouse developmental mutants. Here we report the cloning of a new Pax gene, Pax-9. Most of the DNA sequence encoding the highly conserved paired domain has been determined and compared with previously known paired domains. This comparison classifies Pax-9 as a member of the same subgroup as Pax-1/undulated. By analysis of the segregation of a Pax-9 restriction fragment length polymorphism and a large number of simple sequence length polymorphisms in an interspecific C57BL/6 x Mus musculus mollosinus backcross, Pax-9 was mapped close to the D12Nds1 locus on the proximal part of Chromosome (Chr) 12.

Effect of a partial deletion of Y chromosome on in vitro fertilizing ability of mouse spermatozoa

The effect of a partial deletion of Y chromosome on sperm fertilizing ability was investigated through an in vitro fertilization technique. Epididymal spermatozoa of a congenic line, B10.BR-Ydel, which is characterized by a high incidence of abnormal spermatozoa, revealed a significantly lower in vitro fertilization rate (22%) than that (79%) of its control strain (B10.BR/SgSn), which has a normal-sized Y chromosome. Incidence of capacitated spermatozoa as determined by chlortetracycline fluorescence assay was significantly lower in B10.BR-Ydel than in B10.BR/SgSn spermatozoa. The fertilization rate was significantly improved when B10.BR-Ydel spermatozoa were separated from the supernatant of sperm suspension by Percoll gradient centrifugation. A reconstitution experiment revealed that the B10.BR-Ydel spermatozoa were more sensitive to the inhibitory effect of the supernatant than B10.BR/SgSn spermatozoa. Spermatozoa from F1 (C57BL/6N male x B10.BR-Ydel female) males showed higher fertilization rates than those from F1 (B10.BR.Ydel male x C57BL/6N female) males. These observations suggest that not only the morphology but also the fertilizing ability of spermatozoa is directly related to partial deletion of Y chromosome.

[Genetic profile of LIBP/1 inbred strain derived from the Kunming outbred stock of the mouse]

To make the genetic profile of the LIBP/1 inbred strain obtained from Kunming mice, the most widely used outbred stock in China, 26 loci were examined. The genotypes of four kinds of coat color genes were a/a, B/B, c/c and D/D. The results of testing 21 biochemical marker genes showed Akp-1b, Amy-1a, Car-2a, Ce-2a, Es-1b, Es-3a, Es-10a, Es-11a, Gpd-1a, Gpi-1a, Gus-1b, Hbbs, Idh-1a, Ldr-1a, Mod-1a, Mup-1b, Pep-3b, Pgm-a, Sep-1b, Tam-1c, and Trfb. The H-2 gene loci were Kb and Db.

The amplified long genomic sequence (ALGS) located in the centromeric regions of mouse chromosomes

We reported previously that the haploid genome of standard strains of laboratory mice contains approximately 70 copies of an amplified long genomic sequence, designated ALGS, that includes a retroposon of the gene for elongation factor 2 (MER). The length of each repeating unit is more than 60 kb, and the sequence of the unit is highly conserved among the repeats. In the present study, Southern blot analysis of the genomes of wild rodents demonstrated that the ALGS is present in all subspecies of Mus musculus and is abundant in M. spicilegus, whereas it is absent in M. spretus as well as in Rattus and other closely related genera. This result indicates that the amplification occurred after the species differentiation with the genus Mus and at least prior to the differentiation of subspecies of M. musculus. To locate chromosomal positions of the ALGS, in situ hybridization was carried out with laboratory strains and wild mice. It appears that the ALGS is located in the centromeric regions of most chromosomes in laboratory mice, M. musculus and M. spicilegus, whereas no positive signals were observed with M. spretus, in accordance with the results from the Southern blotting analysis.