Two independent and interactive DNA-binding subdomains of the Pax6 paired domain are regulated by alternative splicing

Vertebrate Pax proteins share a conserved 128-amino-acid DNA-binding motif, the paired domain. The PAX6 gene, which is mutated in the murine Small eye and human aniridia developmental defects, also encodes a second protein with a 14-amino-acid insertion in the paired domain. This protein, which arises by alternative mRNA splicing, exhibits unique DNA-binding properties. Unlike other paired domains, which bind DNA predominantly by their amino termini, the extended Pax6 paired domain interacts with DNA exclusively through its carboxyl terminus. This property can be stimulated by deletion of 30 amino-terminal residues from the Pax6 or Pax2 paired domains. Thus, the insertion acts as a molecular toggle to unmask the DNA-binding potential of the carboxyl terminus. The functional nonequivalence of the two Pax6 proteins is underscored by a T-->C mutation at position -3 of the alternative splice acceptor site that changes the ratio of the two isoforms and causes a distinct human ocular syndrome.

Dissection of the Drosophila paired protein: functional requirements for conserved motifs

The Drosophila paired gene encodes three conserved motifs: a homeodomain, paired domain and PRD (his/pro) repeat. To investigate the functional importance of the PRD repeat and paired domain, we tested deletion mutants using an ectopic expression assay in embryos. Our results suggest that the PRD repeat is not required for the in vivo regulation of the target genes, engrailed and gooseberry. However, the PRD repeat appears to be embedded within a proline-rich transcriptional activation domain required for the regulation of these genes. Our analysis of the paired domain indicated that its N-terminal half, which is required for DNA binding in vitro, is also required for in vivo function, whereas surprisingly, the C-terminal half is dispensable for the regulation of engrailed and gooseberry.

[Heel reconstruction by the composite island flap of the lower leg]

From 1987, 6 to 1992, 6 cases of heel defect were repaired successfully by reverse transfer of the composite island flap from the lateral lower leg. The flap, pedicled with peroneal vessels, consisted of skin, subcutaneous tissue, fibula and adjacent muscles. The contour and function were satisfactory.

Phylogenetic analysis of species of the meso-diaminopimelic acid-containing genera Brevibacterium and Dermabacter

16S rRNA gene sequencing studies were performed on Dermabacter hominis and four meso-diaminopimelic acid-containing species of the genus Brevibacterium. Phylogenetic analysis revealed a close association between Dermabacter hominis and representatives of the lysine-containing genera Arthrobacter, Micrococcus, and Renibacterium. By contrast, the genus Brevibacterium formed a distinct line of descent within the high-guanine-plus-cytosine-containing actinomycetes, displaying no specific affinity with any other organism examined.

Oncostatin-M is an autocrine growth factor in Kaposi's sarcoma

Oncostatin-M is a cytokine produced by macrophages and activated T lymphocytes that has recently been shown to be a mitogen for AIDS-related Kaposi's sarcoma (KS)-derived spindle cells. The significance of oncostatin-M production in AIDS-related KS in vivo, however, remains unknown. In this study we wanted to determine whether oncostatin-M is expressed in vivo in patients with HIV-I-related KS, define the cell types that express this cytokine, and compared with the control tissues from HIV-I-negative individuals. A second objective of our study was to define the expression of oncostatin-M in AIDS-KS-derived spindle cell isolates cultured in vitro and to determine whether oncostatin-M is an autocrine growth factor for these KS cells. We have determined that oncostatin-M is not expressed in any of the several organs examined in control cases, whereas the tumor tissue obtained from the skin biopsies of HIV-I-infected cases with KS displayed oncostatin-M expression in the spindle cell components of the tumor, as well as the cells lining the vascular structures, smooth muscle cells lining the eccrine sweat glands, and the epidermal layers of the skin. Furthermore, uninvolved skin of patients with HIV-related KS express oncostatin-M in the cells lining normal vessels. The mRNA polymerase chain reaction analysis confirmed findings in the primary tissues and showed expression in all of the AIDS-KS-derived spindle cell isolates examined. We have also shown with the use of oncostatin-M-specific antisense oligodeoxynucleotides that KS cell proliferation is inhibited, which correlated with a more precipitous decline in the production of interleukin-6 by these cells. We conclude that oncostatin-M is only expressed in the skin and KS tumor of HIV-I-infected individuals. Furthermore, we provide evidence that oncostatin-M is an autocrine growth factor for KS.

Evidence for a close phylogenetic relationship between Melissococcus pluton, the causative agent of European foulbrood disease, and the genus Enterococcus

The 16S rRNA gene sequence of Melissococcus pluton, the causative agent of European foulbrood disease, was determined in order to investigate the phylogenetic relationships between this organism and other low-G + C-content gram-positive bacteria. A comparative sequence analysis revealed that M. pluton is a close phylogenetic relative of the genus Enterococcus.

Identification of a Pax paired domain recognition sequence and evidence for DNA-dependent conformational changes

Pax genes encode a family of developmentally regulated transcription factors that have been implicated in a number of human and murine congenital disorders, as well as in tumorigenesis (Gruss, P., and Walther, C. (1992) Cell 69, 719-722; Hill, R., and van Heyningen, V. (1992) Trends Genet. 8, 119-120; Chalepakis, G., Tremblay, P., and Gruss, P. (1992) J. Cell Sci. Suppl. 16, 61-67; Maulbecker, C. C., and Gruss, P. (1993) EMBO J. 12, 2361-2367; Walther, C., Guenet, J. L., Simon, D., Deutsch, U., Jostes, B., Goulding, M. D., Plachov, D., Balling, R., and Gruss, P. (1991) Genomics 11, 424-434; Barr, R. G., Galili, N., Holick, J., Biegel, J. A., Rovera, G., and Emanuel, B. S. (1993) Nature Genet. 3, 113-117). These genes are defined by the presence of an evolutionarily conserved DNA binding domain, termed the paired domain. The structure and the DNA binding characteristics of the paired domain remain largely unknown. We have utilized repetitive rounds of a polymerase chain reaction-based selection method to identify the optimal DNA binding sequences for the Pax-2 and Pax-6 paired domains. The results suggest that the paired domain family of peptides bind similar DNA sequences. Identification of this binding site has revealed an important structural clue regarding the mechanism of paired domain binding to DNA. CD and NMR structural analyses of the purified Pax-6 paired domain reveal it to be largely structureless in solution. Upon binding the recognition sequence, the complex becomes markedly less soluble and displays CD spectroscopic evidence of significant alpha-helical structure.

Isolation and characterization of the mouse heme oxygenase-1 gene. Distal 5' sequences are required for induction by heme or heavy metals

Mouse genomic fragments encoding heme oxygenase-1 (HO-1) were isolated from a recombinant lambda library by in situ plaque hybridization. The mouse HO-1 gene, approximately 7 kilobase pairs (kbp) in length, is organized into 5 exons and 4 introns. The primary structure of the exons and 1287 base pairs (bp) of the 5'-flanking region was determined. The deduced amino acid sequence of the mouse HO-1 gene is identical to that of p32, initially identified as a stress-induced protein in mouse BALBc/3T3 cells. A single, major transcription initiation site is utilized for constitutive and heme- or metal-induced expression of the HO-1 gene in mouse hepatoma (Hepa) cells. The transcriptional activity of the 5'-flanking region was examined by transient expression assays using the chloramphenicol acetyltransferase gene as the reporter gene. Basal promoter activity in several cell lines was localized to within 149 bp of the upstream sequence by deletion analysis. This proximal promoter region of the mouse HO-1 gene contains several sequence elements that are not only conserved in both the rat and human HO-1 genes but also resemble consensus binding sites of various transcription factors including AP-1, AP-4, C/EBP and c-Myc:Max/USF. Heavy metals activate HO-1 gene transcription and the rat gene contains a putative metal regulatory element (Müller, R. M., Taguchi, H., and Shibahara, S. (1987) J. Biol. Chem. 262, 6795-6802) that is completely conserved in the mouse gene. Transient expression analyses, however, indicate that this sequence, which contains a core heptanucleotide, TGCACTC, identical to that of the strongest metal regulatory element of the mouse metallothionein-1 gene, is not responsive to Cd2+ or Zn2+. Stable transfection of constructs containing the entire mouse HO-1 gene and various portions of the 5'-flanking region into rat C6 glioma cells and simultaneous, quantitative analysis of the mouse and rat HO-1 mRNAs indicate that distal 5' sequences, between positions -3.5 and -12.5 kbp, are required for induction of mouse HO-1 gene transcription by both heme and heavy metals. A 5-7-fold difference in the levels of induction between stably integrated and transiently expressed mouse HO-1 gene constructs is observed in this cell line.(ABSTRACT TRUNCATED AT 400 WORDS)

Possibility of signal transduction through microfilaments below the membrane following ligand-receptor interaction

In this paper, we describe the changes of microfilament assembly and 3H-TdR incorporation in mouse ascites liver cancer cells under the action of concanavalin A (ConA) and laminin (LN). We have also studied the variation of 3H-TdR incorporation induced by destroying microfilaments with cytochalasin B (CB) following ConA and LN binding with their membrane receptors. It was found that ConA and LN interactions with their membrane receptors could induce the assembly of microfilaments below the membrane and promote DNA synthesis in these cells, but this effect was inhibited when microfilaments were destroyed by CB treatment. These results suggest that microfilaments might play a role in transferring signals from the membrane to the nucleus.

Aeromonas enteropelogenes and Aeromonas ichthiosmia are identical to Aeromonas trota and Aeromonas veronii, respectively, as revealed by small-subunit rRNA sequence analysis

The 16S rRNA gene sequences of the type strains of Aeromonas enteropelogenes and Aeromonas ichthiosmia were determined by polymerase chain reaction direct sequencing in order to clarify their interrelationships with other aeromonad species. On the basis of 16S rRNA gene sequence analysis, A. enteropelogenes and A. ichthiosmia were found to be identical to Aeromonas trota and Aeromonas veronii, respectively.

AIDS-associated Kaposi's sarcoma pathogenesis, clinical features, and treatment

Kaposi's sarcoma is the most common tumor associated with HIV-1 infection. Kaposi's sarcoma is seen most frequently among homosexual or bisexual men, the reasons for which are unknown. Culture of Kaposi's sarcoma spindle cells has been very useful to study various biologic features of the tumor and to develop novel drug therapy. Treatment of AIDS-associated Kaposi's sarcoma is planned based on tumor burden, immunologic status of the patient, and bone marrow rescue. All treatment types at present only provide palliation, whereas efforts to find more effective therapy and possibly preventive therapy are in progress.

Identification of tlc and gltA mRNAs and determination of in situ RNA half-life in Rickettsia prowazekii

RNAs of Rickettsia prowazekii, an obligate intracytoplasmic bacterium, have been identified and analyzed by an RNase protection assay. Total RNA, a mixture of host cell RNA and rickettsial RNA, was isolated from rickettsia-infected mouse L929 cells by the hot-phenol method. After hybridization with specific antisense RNA probes and digestion with RNase, the protected products were analyzed by electrophoresis and autoradiography. The results show that there is only one mRNA species for the ATP/ADP translocase gene (tlc) but two mRNA species for the citrate synthase gene (gltA). RNA half-lives were determined by measuring the RNA remaining after addition of rifampin. The half-lives of tlc mRNA, gltA mRNA I, and gltA mRNA II in R. prowazekii are 8.4 +/- 0.6, 12.3 +/- 1.3, and 20.5 +/- 1.8 min, respectively. However, the half-lives of tlc mRNA and gltA mRNA I in recombinant Escherichia coli strains are 2.9 +/- 0.1 and 1.4 +/- 0.1 min, respectively. The 16S rRNA in R. prowazekii was also examined and shown to be stable.

A study on the effect of lesions of area 7 of the parietal cortex on the short-term visual spatial memory of rhesus monkeys (Macaca mulatta)

This research is focused on the contribution of area 7 to the short-term visual spatial memory. Three rhesus monkeys (Macaca mulatta) were trained in the direct delayed response task in which 5 delay intervals were used in each session. When each monkey reached the criterion of 90% correct responses in 5 successive sessions, two monkeys underwent a surgery while the other one received a sham operation as a control. In the first stage of the surgery, bilateral areas 7a, 7b and 7ip of the parietal cortex of two monkeys were precisely lesioned. After 7 days of recuperation, the monkeys were required to do the same task. The average percentage of correct responses in the lesioned animals decreased from 94.7% to 89.3% and 93.3% to 82.0% respectively (no significance, P > 0.05, n = 2). In addition, the monkeys' complex movements were mildly impaired. The lesioned monkeys were found to have difficulty picking up food from the wells. In the second stage, bilateral area 7m was lesioned. In the 5 postoperative sessions, the average percentage of correct responses in one monkey, with a relatively precise 7m lesion, decreased from 94.7% to 92.2% (no significance, P > 0.05), while the other monkey, with widely spread necrosis of lateral parietal cortex, showed an obvious decline in performance, but still over the chance level. After 240 trials this monkey reattained the normal criterion.(ABSTRACT TRUNCATED AT 250 WORDS)

Replantation of a multiple digit and circular palm amputation: a case report

A case of successful replantation of multiple digits and circular palm amputation caused by an industrial punch force is reported. The two-level amputation was reconstructed by first replanting the severed fingers to the palmar segment and then connecting the palm segment to the hand stump. An arterial crisis was treated with urokinase, and postoperative functional recovery is described.

Light-scattering measurements of monomer size, monomers per aggregate, and fractal dimension for soot aggregates in flames

A new method for the in situ optical determination of the soot-cluster monomer particle radius a, the number of monomers per cluster N, and the fractal dimension D is presented. The method makes use of a comparison of the volume-equivalent sphere radius determined from scattering-extinction measurements RSe and the radius of gyration Rg, which is determined from the optical structure factor. The combination of these data with the measured turbidity permits for a novel measurement of D. The parameters a and N are obtained from a graphical network-analysis scheme that compares R(se) and Rg. Corrections for cluster polydispersity are presented. The effects of uncertainty in various input parameters and assumptions are discussed. The method is illustrated by an application to data obtained from a premixed methane-oxygen flame, and reasonable values of a, N, andD are obtained.

Extensive and selective mutation of a rearranged VH5 gene in human B cell chronic lymphocytic leukemia

B cell chronic lymphocytic leukemia (CLL) is the malignant, monoclonal equivalent of a human CD5+ B cell. Previous studies have shown that the VH and VL genes rearranged and/or expressed in CLL have few and apparently random mutations. However, in this study, we have found that the rearranged VH251 gene, one of the three-membered VH5 family, has extensive and selective mutations in B-CLL cells. Somatic mutation at the nucleotide level is 6.03% in B-CLLs whereas the somatic mutation levels are much lower in CD5+ and CD5- cord B cells, adult peripheral blood B cells, and Epstein-Barr virus-transformed CD5+ B cell lines (0.45, 0.93, and 1.92%, respectively). Complementary determining region 1 (CDR1) mutation in CLLs is particularly prevalent, and interchanges in CDRs often lead to acquisition of charge. Analysis of somatic mutations and mutations to charged residues demonstrated that the mutations in CLLs are highly selected.

Studies on the ribosomal RNA operons of Listeria monocytogenes

A 23S rRNA gene of Listeria monocytogenes was cloned into pUC19 on a 6.2-kb Pst I fragment. Hybridisation studies demonstrated the presence of the 5S and partial 16S rRNA genes within the clone. The nucleotide sequence of the region encoding the 23S rRNA was found to be highly homologous with those of other low G + C Gram-positive bacteria. The 16S-23S intergenic spacer region was amplified using PCR technology and revealed two product sizes, the larger of which contained tRNA(Ala) and tRNA(Ileu) genes. Further tRNA genes were found downstream of the 5S rRNA gene.

PCR cloning and nucleotide sequence determination of the 18S rRNA genes and internal transcribed spacer 1 of the protozoan parasites Cryptosporidium parvum and Cryptosporidium muris

The genes encoding 18S rRNA and internal transcribed spacer 1 (1TS1) of Cryptosporidium parvum and Cryptosporidium muris were amplified from oocysts by PCR utilizing primers complementary to conserved regions of the 5' end of 18S and 5.8S rRNA. PCR products were cloned and the complete nucleotide sequences of two clones of each Cryptosporidium species were determined. The 18S rRNA genes of C. parvum and C. muris showed more than 99% sequence identity.

Analysis of VH251 gene mutation in chronic lymphocytic leukemia (CLL) and normal B-cell subsets

B-cell chronic lymphocytic leukemia (CLL) is the malignant, monoclonal equivalent of a human CD5+ B cell. Previous studies have shown that the VH and VL genes rearranged and/or expressed in CLL have low and random mutations. In this study, however, we have found that the rearranged VH251 gene, one of the three-membered VH5 family, has extensive and selective mutations in B-CLL cells. Somatic mutation at the nucleotide level is 6.03%, and there is a high ratio of replacement to silent mutation in CDRs relative to FWRs. CDR1 mutation is particularly prevalent, and interchanges often lead to acquisition of charge. In VH251 rearranged in CD5+ and CD5- cord-blood B cells, adult peripheral-blood B cells and EBV-transformed CD5+ B-cell lines, the somatic mutation levels are much lower (0.45%, 0.93%, and 1.92%, respectively) with concomitantly lower replacement to silent ratios in CDRs relative to FWRs. The extensive and highly selective somatic mutation of VH251 used in CD5+ CLL cells strongly suggests that part of CLL is generated under the influence of antigen selection and stimulation.

[Studies on the quality of fructus Cnidii--comparison of antibacterial action]

Comparative studies on antibacterial and antifungal action of the fruits of C. monnieri from four habitats and two other species of Cnidium showed they had inhibitory potency to some bacterial and fungi in vitro. C. monnieri and C. salium were more effective than C. dahuricum in antibacterial activities. C. monnieri had higher antifungal effect than C. salium and C. dahuricum.