- Email: [email protected]
Transgenic mice to study the development and function of the immune system
Cell Biology International
Reports, Vol. 74, Abstracts Supplement
Ll
NUCLEAR RECEPTORS AND DEVELOPMENT. Pierre Chambon, LGME/CNRS and U.l84/1NSERM, Faculte de Medecine, 67085 Strasbourg, France. Steroid/thyroid hormone and retinoic acid of nuclear receptors (RARs) belong to the famil 1' receptors which act as ligand-inducib e transcriptional enhancer factors by binding to specific cisacting responsive ONA elements. In vivo and in vitro structure/function studies on the oestrogeii; mstin and glucocorticoid receptors using in vitro engineered mutants and chimeric receptoFS expressed in animal and {east.cells have revealed the existence of several unctional domains responsible for ligand binding., nuclear localization, DNA binding and activation of dimerization, transcription. These studies (1-3 and Refs therein) will be summarized and a model aimed at explaining how the oestrogen receptor may function will be discussed. A comparison of the structure of the three human and mouse RAR-a, RAR-8 and RAR-7 and of which have been recently cloned in their isoforms, our laboratory (4 and Refs therein), led us to may specifically control the suggest that the subsets of genes and thus expression of dif F erent account for the multiple effects of retinoic acid and cell differentiation. embryogenesis during studies on mouse embryo In situ hybridization su port this suggestion, since sections strongly exhibit specific spatioRAR-a, RAR-8 and RA Ii -7 which are also temporal patterns of ex ression, OP the cellular retinoic distinct from those
L3
TRANSGENIC MICE TO STUDY THE DEVELOPMENT AND FUNCTION OF THE IMMUNE SYSTEM
Michael Steinmetz, Central Research Units, F.Hoffmann-La Roche Ltd, Recognition of foreign system is controlled by
CH-4002 antigens
Basel, Switzerland by the itmnune
T lymphocytes which express a highly variable receptor complementary to the diversity of foreign determinants. Variability of T-cell receptors (TCR) is generated through somatic rearrangements of gene segments during T-cell development. Immature T cells are selected in the thymus to form a repertoire capable of recognizing foreign antigens in association with self major histocompatibility complex molecules (positive selection) and tolerant of self determinants (negative selection). Allelic exclusion ensures that a given T cell will express only one type of TCR. Over the past five years we have studied TCR gene rearrangement (l), allelic exclusion (2) and thymic selection (3) in transgenic mice containing TCRgenes in germline configuration and/or in a functionally rearranged form. These experiments will be reviewed and results from more recent studies
will
be discussed.
References 1.
2.
van Meerwijk et al. (1990). T-cell specific rearrangement of T-cell receptor beta transgenes in mice. EMBO J. 9, 1057-1062. Y. Uematsu et al. (1988T. In transgenic mice the introduced functional T-cell receptor beta gene prevents expression of endogenous genes. Cell 52, 831-841.
J.
3. P. KiTielow et al. (1988). Tolerance in T-cell receptor transgenic mice involves deletion of nonmature
742-746.
CD4+CD8+thymocytes.
Nature
333,
1990
L2 mxANIsmoF
aa+ -Tim. Dept. -MY, Centers and B. Ceccarelli Institute, Univ. of Milano.
Meldolesi. Llw SJZaffaele
m
OJR and
their cells of all types F&sting keep concentration of cytosolic Ca2+, [CaBtli, very low it (uptovaluesin the @4 (s 0.1 pt4) and increase range) onlyafterappropriate stimulation, minly via the activation of specific channels in the plasma mmbrane and/or intracellular organelles. ca2t ChanneJs of dtiple classes surface (activated by voltage changes, specific ligands or second messengers) are variously expressed in while intracellular chemels of different cells, two types (sensitive to IP3 and blocked by distribution. exhibit wides~mad bill and pharmcological experiments indicate these last channels tobelocatedin at lesat. partially distinct orgmelles. lbe ryanodine orgsnelle is believed to be - specific Sofar it responsible for [CaftJi oscillatims. has not yet been identified with certainty except wbere it consists in the in mscle cells, smcoplamic reticulun. In wntrsst, the IP3organelle (identified in Purkinje sensitive neurons by high resolution hmmocyto&mistry amrker ) the specific receptor as the using consists inamth-surfaced subccqartaent of the endophic reticulum. Themolecularnekeup ca2t storage of these rapidly exchaneins organellesand their fuucticminghas been further investigated by mapping the distribution of other low affinitypltative canponen ts (Ca2t ATPase; camparedwith high capacity Ca2tbinding proteins) that0funrelatedmicrosoma1canPommt.s.
GENES INVOLVED IN THE COMMITMENT OF PLANT CELLS TO DIFFERENTIATION Jeff Schell, Csaba Koncz, Klaus Palme, Angelo Spena, Thomas Hesse, Thomas Schmiilling, Richard Walden, Jiirgen Schmidt and fiir ZiichMichael John. Max-Planck-Institut tungsforschung, 5000 KBln 30, F.R.G. The molecular mechanisms underlying control of growth and differentiation in higher plant cells remain unknown. It is well documented that plant hormones such as auxins are key elements in the regulation of developmental processes in higher plants, including cell differentiation, cell extension and cell division. It has been proposed that hormone receptors, G-proteins and protein kinases are involved in signal transduction processes controlling various aspects of plant development. We shall discuss the molecular structure of different auxin receptor genes and G-protein entoding genes. The expression of these genes is developmentally regulated. Remarkable variation of expression has been observed specifically in flower tissues. The isolation of other genes potentially involved in plant hormone signal transduction relies on the study of different procaryotic genes known to have a marked effect on plant growth and differentiation. These are TDNA linked genes from &.tumefaciens and A. rhizogenes as well as so-called NOD genes from Rhizobium strains. Finally various gene-tagging approaches will be discussed that are presently used to identify and isolate genes involved in developmental control of plants.
L4
Reports, Vol. 74, Abstracts Supplement
Ll
NUCLEAR RECEPTORS AND DEVELOPMENT. Pierre Chambon, LGME/CNRS and U.l84/1NSERM, Faculte de Medecine, 67085 Strasbourg, France. Steroid/thyroid hormone and retinoic acid of nuclear receptors (RARs) belong to the famil 1' receptors which act as ligand-inducib e transcriptional enhancer factors by binding to specific cisacting responsive ONA elements. In vivo and in vitro structure/function studies on the oestrogeii; mstin and glucocorticoid receptors using in vitro engineered mutants and chimeric receptoFS expressed in animal and {east.cells have revealed the existence of several unctional domains responsible for ligand binding., nuclear localization, DNA binding and activation of dimerization, transcription. These studies (1-3 and Refs therein) will be summarized and a model aimed at explaining how the oestrogen receptor may function will be discussed. A comparison of the structure of the three human and mouse RAR-a, RAR-8 and RAR-7 and of which have been recently cloned in their isoforms, our laboratory (4 and Refs therein), led us to may specifically control the suggest that the subsets of genes and thus expression of dif F erent account for the multiple effects of retinoic acid and cell differentiation. embryogenesis during studies on mouse embryo In situ hybridization su port this suggestion, since sections strongly exhibit specific spatioRAR-a, RAR-8 and RA Ii -7 which are also temporal patterns of ex ression, OP the cellular retinoic distinct from those
L3
TRANSGENIC MICE TO STUDY THE DEVELOPMENT AND FUNCTION OF THE IMMUNE SYSTEM
Michael Steinmetz, Central Research Units, F.Hoffmann-La Roche Ltd, Recognition of foreign system is controlled by
CH-4002 antigens
Basel, Switzerland by the itmnune
T lymphocytes which express a highly variable receptor complementary to the diversity of foreign determinants. Variability of T-cell receptors (TCR) is generated through somatic rearrangements of gene segments during T-cell development. Immature T cells are selected in the thymus to form a repertoire capable of recognizing foreign antigens in association with self major histocompatibility complex molecules (positive selection) and tolerant of self determinants (negative selection). Allelic exclusion ensures that a given T cell will express only one type of TCR. Over the past five years we have studied TCR gene rearrangement (l), allelic exclusion (2) and thymic selection (3) in transgenic mice containing TCRgenes in germline configuration and/or in a functionally rearranged form. These experiments will be reviewed and results from more recent studies
will
be discussed.
References 1.
2.
van Meerwijk et al. (1990). T-cell specific rearrangement of T-cell receptor beta transgenes in mice. EMBO J. 9, 1057-1062. Y. Uematsu et al. (1988T. In transgenic mice the introduced functional T-cell receptor beta gene prevents expression of endogenous genes. Cell 52, 831-841.
J.
3. P. KiTielow et al. (1988). Tolerance in T-cell receptor transgenic mice involves deletion of nonmature
742-746.
CD4+CD8+thymocytes.
Nature
333,
1990
L2 mxANIsmoF
aa+ -Tim. Dept. -MY, Centers and B. Ceccarelli Institute, Univ. of Milano.
Meldolesi. Llw SJZaffaele
m
OJR and
their cells of all types F&sting keep concentration of cytosolic Ca2+, [CaBtli, very low it (uptovaluesin the @4 (s 0.1 pt4) and increase range) onlyafterappropriate stimulation, minly via the activation of specific channels in the plasma mmbrane and/or intracellular organelles. ca2t ChanneJs of dtiple classes surface (activated by voltage changes, specific ligands or second messengers) are variously expressed in while intracellular chemels of different cells, two types (sensitive to IP3 and blocked by distribution. exhibit wides~mad bill and pharmcological experiments indicate these last channels tobelocatedin at lesat. partially distinct orgmelles. lbe ryanodine orgsnelle is believed to be - specific Sofar it responsible for [CaftJi oscillatims. has not yet been identified with certainty except wbere it consists in the in mscle cells, smcoplamic reticulun. In wntrsst, the IP3organelle (identified in Purkinje sensitive neurons by high resolution hmmocyto&mistry amrker ) the specific receptor as the using consists inamth-surfaced subccqartaent of the endophic reticulum. Themolecularnekeup ca2t storage of these rapidly exchaneins organellesand their fuucticminghas been further investigated by mapping the distribution of other low affinitypltative canponen ts (Ca2t ATPase; camparedwith high capacity Ca2tbinding proteins) that0funrelatedmicrosoma1canPommt.s.
GENES INVOLVED IN THE COMMITMENT OF PLANT CELLS TO DIFFERENTIATION Jeff Schell, Csaba Koncz, Klaus Palme, Angelo Spena, Thomas Hesse, Thomas Schmiilling, Richard Walden, Jiirgen Schmidt and fiir ZiichMichael John. Max-Planck-Institut tungsforschung, 5000 KBln 30, F.R.G. The molecular mechanisms underlying control of growth and differentiation in higher plant cells remain unknown. It is well documented that plant hormones such as auxins are key elements in the regulation of developmental processes in higher plants, including cell differentiation, cell extension and cell division. It has been proposed that hormone receptors, G-proteins and protein kinases are involved in signal transduction processes controlling various aspects of plant development. We shall discuss the molecular structure of different auxin receptor genes and G-protein entoding genes. The expression of these genes is developmentally regulated. Remarkable variation of expression has been observed specifically in flower tissues. The isolation of other genes potentially involved in plant hormone signal transduction relies on the study of different procaryotic genes known to have a marked effect on plant growth and differentiation. These are TDNA linked genes from &.tumefaciens and A. rhizogenes as well as so-called NOD genes from Rhizobium strains. Finally various gene-tagging approaches will be discussed that are presently used to identify and isolate genes involved in developmental control of plants.
L4