[200 years of the animal hospital Zurich: A cross-section through the lectures of the exam year 1864]. / 200 Jahre Tierspital Zürich: Ein Querschnitt durch die Vorlesungen des Examenjahrgangs 1864.

INTRODUCTION: The current study analyzed eleven lecture transcripts from the Zurich Veterinary School of the years -1861-1864. The work presents the staff and organizational situation of the school at that time. Lectures concerned mostly clinical subjects, especially special pathology and therapy. The texts were transcribed, summarized and analyzed according to the criteria species, diagnosis and therapy. The drugs were listed. Therapy concepts follow the principles of humoral pathology, but transition to cellular pathology was imminent. The pathogens of infectious diseases are not identified yet, but are suspected to be called «contagions¼.

INTRODUCTION: On dispose de 11 manuscrits de cours des années ­1861­1864 à l'école vétérinaire de Zürich. On présente la situation de l'époque de l'école au point de vue du personnel et de l'organisation. Les cours concernent principalement les branches cliniques, en particulier la pathologie spéciale et la thérapie. Les manuscrits ont été transcrits, résumés et analysés en tenant compte des critères de l'espèce animale, du diagnostic et du traitement. On a établi une liste des médicaments. Les concepts thérapeutiques étaient basés sur les principes de la pathologie humorale mais la transition vers la pathologie cellulaire se dessine. Les agents infectieux n'étaient pas encore identifiés mais on les pressent avec le terme de «contagions¼.

Inscuteable-dependent apical localization of the microtubule-binding protein Cornetto suggests a role in asymmetric cell division.

Drosophila neuroblasts divide asymmetrically along the apical-basal axis. The Inscuteable protein localizes to the apical cell cortex in neuroblasts from interphase to metaphase, but disappears in anaphase. Inscuteable is required for correct spindle orientation and for asymmetric localization of cell fate determinants to the opposite (basal) cell cortex. Here, we show that Inscuteable also directs asymmetric protein localization to the apical cell cortex during later stages of mitosis. In a two-hybrid screen for Inscuteable-binding proteins, we have identified the coiled-coil protein Cornetto, which shows a highly unusual subcellular distribution in neuroblasts. Although the protein is uniformly distributed in the cytoplasm during metaphase, it concentrates apically in anaphase and forms an apical crescent during telophase in an inscuteable-dependent manner. Upon overexpression, Cornetto localizes to astral microtubules and microtubule spin-down experiments demonstrate that Cornetto is a microtubule-binding protein. After disruption of the actin cytoskeleton, Cornetto localizes with microtubules throughout the cell cycle and decorates the mitotic spindle during metaphase. Our results reveal a novel pattern of asymmetric protein localization in Drosophila neuroblasts and are consistent with a function of Cornetto in anchoring the mitotic spindle during late phases of mitosis, even though our cornetto mutant analysis suggests that this function might be obscured by genetic redundancy.

Cloning and characterization of CpG islands of the human chromosome 1p36 region.

CpG islands were identified and localized to chromosome 1p36 by means of pulsed-field gel blot hybridization with 1p36-specific microclone probes. Five CpG islands, designated CpG17, CpG28, CpG60, CpG112a, and CpG112b, were molecularly cloned from corresponding cosmids. All five islands are associated with transcribed sequences, as shown by RNA blot hybridizations. Screening of cDNA libraries with the island-specific genomic probes led to the isolation of two cDNA clones to date. These encode the human transcription factor E2F-2 and the dominant-negative helix-loop-helix gene ID3, respectively. Pulsed-field gel electrophoresis analysis also revealed that these two genes are located next to each other at a distance of about 25 kb.

Determination and regional assignment of grouped sets of microclones in chromosome 1pter-p35.

In an approach to mapping physically the most distal 30 Mb of human chromosome 1p, region-specific clone libraries were generated by microdissection and microcloning. PFGE blot hybridization of single or low-copy microclones against rare-cutter digests of genomic DNA revealed physical linkage for groups of markers. Supplementary PFGE analysis of 31 1p36-p35-specific probes for genetically mapped loci established a total of 15 grouped sets, consisting of altogether 69 markers. Twelve of the grouped sets were located in 1pter-p36.12, as revealed by microcell hybrid mapping; the remaining three were localized proximal to 1p36.12. Regional assignment and ordering of most grouped sets was achieved either by evaluating the included genetic markers or by fluorescence in situ hybridization of representative probes. The genomic extent of individual grouped sets encompassed between 1100 and 2100 kb, covering a total of approximately 22 Mb of the distal chromosome 1p region. One particular grouped set was shown to contain seven polymorphic marker loci that were previously suggested to be distributed across the entire 1pter-p35 region. The increase in the number of hybridization marker probes in 1p36 and their physical mapping is expected to facilitate positional cloning experiments in this region; in particular, the construction of clone contigs may be greatly facilitated.

Mutually exclusive expression of a helix-loop-helix gene and N-myc in human neuroblastomas and in normal development.

We have isolated a novel human gene encoding a helix-loop-helix (HLH) protein by molecularly cloning chromosome 1p36-specific CpG islands. The gene termed heir-1 was localized to the neuroblastoma consensus deletion at 1p36.2-p36.12. Its predicted protein is 95.8% identical to the mouse HLH462 protein and has clear homology to the mouse Id and Drosophila emc proteins. Heir-1 does not encode a basic DNA binding domain as found in basic HLH proteins. The gene is expressed specifically at high abundance in adult lung, kidney and adrenal medulla, but not in adult brain. Despite prominent heir-1 expression in adrenal medulla, which is a prime target for neuroblastomas, 10 out of 12 neuroblastoma-derived cell lines revealed very low levels of heir-1 mRNA. Low heir-1 expression was generally found in tumor cell lines with N-myc overexpression, whereas the two cell lines displaying high heir-1 levels did not overexpress N-myc. Mutually exclusive expression of both genes was also found by in situ hybridization in developing mouse tissues, particularly in the forebrain neuroectoderm. We conclude that heir-1 expression is reduced specifically in the majority of neuroblastomas and suggest an inverse correlation between heir-1 and N-myc expression in neuroblastoma tumors and in embryonic development.

A nuclear protein that binds preferentially to methylated DNA in vitro may play a role in the inaccessibility of methylated CpGs in mammalian nuclei.

The effects of DNA methylation on gene expression and chromatin structure suggest the existence of a mechanism in the nucleus capable of distinguishing methylated and non-methylated sequences. We report the finding of a nuclear protein in several vertebrate tissues and cell lines that binds preferentially to methylated DNA in vitro. Its lack of sequence-specific requirements makes it potentially capable of binding to any methylated sequence in mammalian nuclei. An in vivo counterpart of these results is that methylated CpGs are inaccessible to nucleases within nuclei. In contrast, non-methylated CpG sites, located mainly at CpG islands, and restriction sites not containing this dinucleotide, are relatively accessible. The possibility that DNA methylation acts through binding to specific proteins that could alter chromatin structure is discussed.

Identification of a mammalian protein that binds specifically to DNA containing methylated CpGs.

The effects of DNA methylation on transcription and chromatin structure require that nuclear factors be able to distinguish methylated and nonmethylated DNA. We describe a methyl-CpG binding protein (MeCP) that complexes with a variety of unrelated DNA sequences when they are methylated at CpG. Fifteen or more symmetrically methylated CpG moieties per molecule are required for strong binding under our conditions. Competition experiments show that vertebrate DNAs bind to MeCP, whereas naturally nonmethylated genomes or cloned vertebrate genomes do not bind. Cross-linking experiments detect a 120 kd protein that correlates stringently with MeCP activity. Species and tissue comparisons show that MeCP is widely distributed in mammals except in embryonal carcinoma cell lines, which have very low levels.

Identification of bovine papillomavirus E1 mutants with increased transforming and transcriptional activity.

The E1 open reading frame of bovine papillomavirus type 1 (BPV) has been shown previously to encode trans-acting functions, M and R, that are involved in extrachromosomal replication of the viral genome. We have determined that several E1 mutants mapping in both the M and R regions and a single mutant of the upstream regulatory region have a higher transforming activity on mouse C127 cells than the wild-type genome does. A representative mutant in M, a mutant in R, and the upstream regulatory region mutant were complemented in trans by the wild-type genome, but the two E1 mutants did not complement each other, suggesting that they affect the same inhibitory function. A long terminal repeat-activated clone constructed to express the intact E1 open reading frame reversed the high-transformation phenotype of the mutants. In contrast to the high-copy-number autonomous replication of the wild-type genome, the genomes of the E1 mutants were, as previously described for other E1 mutants, integrated at lower copy numbers in the transformed cells. Relative to the viral genome copy number, both the E1 M and R mutant transformed cells contained an average of 10-fold more BPV-specific transcripts than did the wild-type transformed cells. Cycloheximide treatment of the cells transformed by the E1 mutants did not lead to the rapid 10-fold increase in the accumulation of viral transcripts observed with the wild-type genome. These results suggest either that integration of the BPV genome makes it unresponsive to a labile repressor or that an E1 gene product, containing both M and R sequences, is a repressor of BPV transcription.

Differential regulation of papilloma virus early gene expression in transformed fibroblasts and carcinoma cell lines.

Treatment of bovine papilloma virus (BPV) 1-transformed mouse fibroblasts with cycloheximide led to a 10-fold increase in the amount of viral transcripts, after as little as 1 h of protein synthesis inhibition. Northern blots revealed no qualitative changes in the RNA pattern. Nuclear run-on experiments showed about a 7-fold increase in specific transcriptional activity after cycloheximide treatment. The half-life of BPV1 mRNA was twice as long as in untreated controls. These results indicate that both RNA synthesis and degradation of viral RNA are controlled by labile proteins. Cycloheximide stimulation turned out to be independent of the BPV1 E2 gene activity which enhances viral transcription. Cycloheximide treatment had no effect on the amount of human papilloma virus (HPV) 18 transcripts in cervical carcinoma derived HeLa and C4-1 cells. Transcription of HPV16 in the cervical carcinoma line SiHa was likewise unaffected. The differential regulation of transcription in transformed fibroblasts and cancer-derived cells, and the significance for malignant conversion are discussed.