Proteome analysis of chemically induced mouse liver tumors with different genotype

Mouse liver tumors frequently harbor mutations in Ha-ras, B-raf, or Ctnnb1 (encoding beta-catenin). We conducted a proteome analysis with protein extracts from normal mouse liver and from liver tumors which were induced by a single injection of N-nitrosodiethylamine (DEN) as initiator followed by multiple injections of two different polychlorinated biphenyls (PCBs) as tumor promoters, or corn oil as a control. Liver tumors were stratified into two classes: they were either mutated in Ctnnb1 and positive for the marker glutamine synthetase (GS(+)), or they lacked Ctnnb1 mutations and were therefore GS-negative (GS(-)). Proteome analysis by 2-DE and MS revealed 98 significantly deregulated proteins, 44 in GS(+) and 54 in GS(-) tumors. Twelve of these proteins showed expression changes in both tumor types, but only seven of them were deregulated in the same direction. Several of the identified enzymes could be assigned to fundamental metabolic or other cellular pathways with characteristically different alterations in GS(+) and GS(-) tumors such as ammonia and amino acid turnover, cellular energy supply, and calcium homeostasis. Our data suggest that GS(+) and GS(-) tumor cells show a completely different biology and use divergent evolutionary strategies to gain a selective advantage over normal hepatocytes.     

Phytochrome Control of Its Own Synthesis in Pisum sativum

An analysis of phytochrome synthesis in Pisum seedlings by measuringthe activity of polysomal polyadenylated RNA (poly-A⁺-RNA) codingfor phytochrome apoprotein showed phytochrome control of itsown synthesis; brief red-light irradiation of pea seedlingsinhibited the activity of the RNA, and the red-light effectwas red/far-red reversible. ⁴ Permanent address: Biology Department, Faculty of Science,University of Tokyo, Hongo, Tokyo 113, Japan. (Received August 13, 1984; Accepted September 17, 1984)     

Über Veränderungen der plasmatischen Feinstrukturen während des Welkens

Zusammenfassung Wurzelspitzen der Erbse undDrosophyllum-Drüsen wurden in normalem, gewelktem und (nur beiDrosophyllum) in wieder aufgefrischtem Zustand elektronenmikroskopisch nach Osmium-Bichromat-Fixierung und Einbettung in Vestopal untersucht.Bei Zellen aus dem Rindenmeristem der Erbsenwurzeln schrumpfen durch den Wasserentzug alle Zellkomponenten, besonders die Mitochondrien. Der Kern wird pyknotisch. Alle plasmatischen Lamellen, besonders die Golgi-Zisternen, verklumpen und entmischen sich häufig. Teilweise entstehen daraus myelinartige Membranknäule, besonders in den Rindenzellen aus der Streckungszone. Diese Zellen schrumpfen scheinbar nicht so stark. Sie enthalten dagegen häufig geplatzte Mitochondrien und Plastiden. Es wird diskutiert, wieweit diese Effekte artefiziell sind.Die Drüsenzellen vonDrosophyllum verhalten sich in mancher Hinsicht ähnlich wie die Meristemzellen der Erbsenwurzeln. Membranzerstörungen sind selten. Während des Welkens entsteht in ihnen ein typisches Ergastoplasma, das in den normalen Drüsen fehlt. Dieses verschwindet beim Auffrischen der Blätter wieder. Ebenso normalisieren sich alle anderen Zellkomponenten.Die Untersuchungen zeigen, wie veränderlich die Feinstruktur des Protoplasten ist und geben einige Hinweise über die Vorgänge beim Dürretod.Mit 17 TextabbildungenHerrn Prof. Dr.W. Schumacher zum 60. Geburtstag gewidmet.     

Mechanisms of rapid induction of interleukin-22 in activated T cells and its modulation by cyclosporin a

IL-22 is an immunoregulatory cytokine displaying pathological functions in models of autoimmunity like experimental psoriasis. Understanding molecular mechanisms driving IL-22, together with knowledge on the capacity of current immunosuppressive drugs to target this process, may open an avenue to novel therapeutic options. Here, we sought to characterize regulation of human IL22 gene expression with focus on the established model of Jurkat T cells. Moreover, effects of the prototypic immunosuppressant cyclosporin A (CsA) were investigated. We report that IL-22 induction by TPA/A23187 (T/A) or αCD3 is inhibited by CsA or related FK506. Similar data were obtained with peripheral blood mononuclear cells or purified CD3(+) T cells. IL22 promoter analysis (-1074 to +156 bp) revealed a role of an NF-AT (-95/-91 nt) and a CREB (-194/-190 nt) binding site for gene induction. Indeed, binding of CREB and NF-ATc2, but not c-Rel, under the influence of T/A to those elements could be proven by ChIP. Because CsA has the capability to impair IκB kinase (IKK) complex activation, the IKKα/β inhibitor IKKVII was evaluated. IKKVII likewise reduced IL-22 induction in Jurkat cells and peripheral blood mononuclear cells. Interestingly, transfection of Jurkat cells with siRNA directed against IKKα impaired IL22 gene expression. Data presented suggest that NF-AT, CREB, and IKKα contribute to rapid IL22 gene induction. In particular the crucial role of NF-AT detected herein may form the basis of direct action of CsA on IL-22 expression by T cells, which may contribute to therapeutic efficacy of the drug in autoimmunity.     

Die Hypokotylfarbe als Markierungsfaktor von Genomstufen der Zuckerrübe

Zusammenfassung In zunehmendem Maße werden anisoploideBeta-Rübensorten angebaut, deren zytologische Kontrolle zwecks Feststellung der Genomstufenprozentanteile recht arbeitszeitaufwendig ist. Übereinstimmend mit polnischen Autoren wurde festgestellt, daß die Hypokotylfarbe ein geeigneter Markierungsfaktor für die einzelnen Genomstufen darstellt. Kreuzt man tetraploide Pflanzen, die ein grünes Hypokotyl besitzen, mit diploiden Pflanzen, die ein rosa Hypokotyl aufweisen, so erhält man von dem tetraploiden Partner tetraploide grüne und triploide hellbraune, von dem diploiden Partner diploide rosa und triploide hellbraune Nachkommenschaften. Die in bezug auf die Hypokotylfarbe heterozygoten Pflanzen kann man demnach von den homozygot grünen und homozygot rosa Individuen unterscheiden. Die Kreuzung diploid grünxtetraploid rosa ist für diese Zwecke nicht brauchbar, da sich die triploiden Heterozygoten mit einem grünen und zwei rosa Allelen in der Hypokotylfarbe nicht deutlich von den homozygoten rosa Pflanzen abheben. Auf die Bedeutung dieser Markierungsmöglichkeit für bestimmte Forschungsprobleme, die Züchtung und die Saatgutkontrolle wird hingewiesen.     

The origin of modern crocodyliforms: new evidence from the Cretaceous of Australia

While the crocodyliform lineage extends back over 200 million years (Myr) to the Late Triassic, modern forms-members of Eusuchia-do not appear until the Cretaceous. Eusuchia includes the crown group Crocodylia, which comprises Crocodyloidea, Alligatoroidea and Gavialoidea. Fossils of non-crocodylian eusuchians are currently rare and, in most instances, fragmentary. Consequently, the transition from Neosuchia to Crocodylia has been one of the most poorly understood areas of crocodyliform evolution. Here we describe a new crocodyliform from the mid-Cretaceous (98-95 Myr ago; Albian-Cenomanian) Winton Formation of Queensland, Australia, as the most primitive member of Eusuchia. The anatomical changes associated with the emergence of this taxon indicate a pivotal shift in the feeding and locomotor behaviour of crocodyliforms-a shift that may be linked to the subsequent rapid diversification of Eusuchia 20 Myr later during the Late Cretaceous and Early Tertiary. While Laurasia (in particular North America) is the most likely ancestral area for Crocodylia, the biogeographic events associated with the origin of Eusuchia are more complex. Although the fossil evidence is limited, it now seems likely that at least part of the early history of Eusuchia transpired in Gondwana.     

Ratjadone and leptomycin B block CRM1-dependent nuclear export by identical mechanisms

Research on the export of proteins and nucleic acids from the nucleus to the cytoplasm has greatly gained from the discovery that the actinobacterial toxin leptomycin B (LMB) specifically inactivates the export receptor chromosomal region maintenance 1 (CRM1). Recently, it was shown that myxobacterial cytotoxins, named ratjadones (RATs), also bind to CRM1 and inhibit nuclear export. However, the reaction mechanism of RATs was not resolved. Here, we show that LMB and RAT A employ the same molecular mechanism to inactivate CRM1. Alkylation of residue Cys528 of CRM1 determines both LMB and RAT sensitivity and prevents nuclear export of CRM1 cargo proteins.     

Genetic definition of a further gene region and identification of at least three different histocompatibility genes in the rat major histocompatibility system

Two new recombinant haplotypes of the rat major histocompatibility system,RT1, have been detected in [LEW.1A (RT1 ^a ) ×LEW.1W (RT1 ^u )] × LEW 1N(RT1 ⁿ ) segregating hybrids. Recombinantr3 carries theRTL1. A region (determining classical transplantation antigens) and theRT1.B region (determining strong mixed lymphocyte reactivity and genetic control of antipolypeptide immune responsiveness) of the RT1^a parent, bur rejects RT1^a skin grafts. Recombinantr4 carries theA andB regions of the RT1^u parent, but rejects RT1^u skin grafts. The two histocompatibility genes detected are allelic to each other. The relevant locus, designated asH-C, maps to theB-region side of theRT1 system and appears to mark a thirdRT1 gene region,RT1.C. Availability of haplotypes r3 andr4 allowed the definition of a histocompatibility locus in theB region,H-B. The products ofH-C, H-B and of the previously describedH-A gene vary in antigenic strength.