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The acidic domain, the human version and the protein interaction of the ETS transcription factor SPI-C

Carlsson, Robert LU (2004)
Abstract (Swedish)
Popular Abstract in Swedish

Immunsystemet skyddar kroppen mot infektion. För att kunna skydda mot infektion krävs att immunsystemet är utrustat med kraftfulla biokemiska motmedel. Ett sådant motmedel är antikroppar. Antikroppar är proteiner som känner igen och specifikt binder till andra molekyler via en s k molekylbindande klyfta. När antikropparna har bundit in till en molekyl på t ex en bakteries yta markeras bakterien för destruktion av immunsystemets andra proteiner och celler. De celler som producerar antikroppar kallas för B-lymfocyter eller B-celler. B-celler nybildas i benmärgen och mjälten hos den vuxna människan. Av alla miljontals B-celler som produceras varje dag uttrycker varje enskild B-cell en typ av... (More)
Popular Abstract in Swedish

Immunsystemet skyddar kroppen mot infektion. För att kunna skydda mot infektion krävs att immunsystemet är utrustat med kraftfulla biokemiska motmedel. Ett sådant motmedel är antikroppar. Antikroppar är proteiner som känner igen och specifikt binder till andra molekyler via en s k molekylbindande klyfta. När antikropparna har bundit in till en molekyl på t ex en bakteries yta markeras bakterien för destruktion av immunsystemets andra proteiner och celler. De celler som producerar antikroppar kallas för B-lymfocyter eller B-celler. B-celler nybildas i benmärgen och mjälten hos den vuxna människan. Av alla miljontals B-celler som produceras varje dag uttrycker varje enskild B-cell en typ av antikroppar. Det medför att varje enskild B-cell känner igen, eller binder till en specifik molekyl, vilket ger den s k specificitet. Om B-cellens antikropp kan binda till någon främmande molekyl på t ex ett virus delar den sig ett flertal gånger men bibehåller sin specificitet och expanderar därmed immunsvaret mot just den främmande molekylen. I sitt slutgiltiga skede utsöndrar varje B-cell, som då kallas plasmacell, upp till 6000 antikroppar/sekund och hjälper på så vis till att skydda kroppen mot infektion av mikroorganismer och virus samt neutraliserar toxiska molekyler som finns i t ex ormgift.



B-cellens utveckling är beroende av att gener, som innehåller information för att producera var sitt protein, avläses, transkriberas, med hjälp av andra unika proteiner som kallas transkriptionsfaktorer. Transkriptionsfaktorer har förmågan att binda till promotorer, regioner av gener som kontrollerar om genen ska transkriberas eller inte. Transkription av en viss gen ger translation (omvandling) av en budbärarmolekyl till proteinet som genen innehåller information för. Proteinet kan sedan påverka cellen att bli en B-cell och slutgiltigt en plasmacell.



Vi har studerat hur en transkriptionsfaktor, SPI-C, aktiverar transkription. För att kunna identifiera de regioner av SPI-C som behövs för transkription tog vi bort de delar av proteinet som inte används för att binda till promotorer. I den undersökningen visade vi att SPI-C från mus behöver en region av negativt laddade aminosyror för att kunna aktivera transkription, samt avsaknad av transkription när vi ersatte de negativt laddade aminosyrorna med neutralt laddade. I den andra undersökningen identifierade vi den mänskliga varianten av SPI-C och undersökte i vilka celler och vävnader den finns i, samt identifierade och karakteriserade genen för mus och mänskligt SPI-C. Den tredje undersökningen gick ut på att identifiera andra proteiner som binder till SPI-C. Vi identifierade ett annat protein, en transkriptionsfaktor, STAT6 och kunde visa att SPI-C och STAT6 kan binda till varandra.



Allergi är beroende av en viss typ av antikropp som kallas för IgE. För att plasmaceller ska kunna producera IgE behöver de transkribera promotorn Ie. Vi kan visa att SPI-C och STAT6 samarbetar för ökad transkription av Ie promotorn vilket kan ha betydelse för reglering av IgE plasmaceller och allergi. (Less)
Abstract
Primary infections and vaccination stimulates the immunesystem to produce memory cells that rapidly respond to reexposure of the same antigen. These memory responses are dependent on an adaptive type of immunity that sustains the reactivity of the immune system by long-lived memory immune cells. From an evolutionary perspective adaptive immunity as such appears to be restricted to jawed vertebrates, since non-jawed vertebrates and invertebrates lack recombining receptors and memory responses to infection. One of the two major celltypes of the adaptive immune response is the B-cell. B-cell development is a tightly controlled process that is dependent on the precise transcriptional regulation of intracellular and membrane bound proteins.... (More)
Primary infections and vaccination stimulates the immunesystem to produce memory cells that rapidly respond to reexposure of the same antigen. These memory responses are dependent on an adaptive type of immunity that sustains the reactivity of the immune system by long-lived memory immune cells. From an evolutionary perspective adaptive immunity as such appears to be restricted to jawed vertebrates, since non-jawed vertebrates and invertebrates lack recombining receptors and memory responses to infection. One of the two major celltypes of the adaptive immune response is the B-cell. B-cell development is a tightly controlled process that is dependent on the precise transcriptional regulation of intracellular and membrane bound proteins. During the evolutionary transition from non-jawed to jawed vertebrates both the immune systems and the regulatory transcription factors have undergone diversification. One diversified group of transcription factors is the SPI-group of the ETS transcription family, that contains the PU.1, SPI-B, SPI-C and SPI-lamprey proteins. The absence of the PU.1 gene results in a complete block of early B-cell development. SPI-B knock-out mice display reduced ability to terminally differentiate into plasma cells. Both PU.1 and SPI-B activate transcription dependent on acidic domains in the N-terminus of the proteins. Previously it was shown that SPI-C can activate transcription from a kappa-Y Ig light chain promoter element. We scrutinised the SPI-C protein and could map an acidic transactivating region to the N-terminus of the protein. SPI-C, in contrary to SPI-B or PU.1, does not form a ternary complex with PIP on a lambda-B light chain enhancer element in electro-mobility shift assays. In addition, we identified the human version of the SPI-C protein and mapped the human and mouse genes. The human SPI-C was, like the mouse orthologue, expressed in the spleen and B-cell lines but not in T-cells or in the thymus. Phylogenetic analysis shows that human SPI-C is closest related to SPI-C orthologues. In order to identify proteins interacting with the SPI-C transcription factor we employed the yeast two hybrid system. In such a screen we identified a partial STAT6 clone (13:45) as an interactor of SPI-C. To confirm that SPI-C and 13:45 interacted in mammalian cells we coexpressed the proteins in the COS7 cell line and performed co-immunoprecipitations. 13:45 or the full length STAT6 was co-immunoprecipitated with the SPI-C protein. STAT6 binds to the I-epsilon promoter that regulate transcription and class switch recombination to the IgE isotype in a IL-4 dependent manner. STAT6 and SPI-C activates an I-epsilon reporter gene synergistically in an IL-4 dependent manner when ectopically expressed in COS7 cells and may thus regulate the induction of class switch recombination to the IgE isotype and allergy. (Less)
Please use this url to cite or link to this publication:
author
opponent
  • Professor Pettersson, Sven
organization
publishing date
type
Thesis
publication status
published
subject
keywords
serology, transplantation, Immunologi, serologi, Immunology, B-lymphocyte, phylogeny, STAT6, SPI-C, transcription
pages
138 pages
publisher
Robert Carlsson, BMC I13, 22184, Lund, Sweden,
defense location
Grubb-salen, Sölvegatan 19, Lund
defense date
2004-10-06 09:00
ISBN
91-628-6195-6
language
English
LU publication?
yes
id
86d762f4-ed5a-4305-8172-fdb3f0d173ea (old id 467302)
date added to LUP
2007-09-07 13:03:30
date last changed
2016-09-19 08:45:02
@phdthesis{86d762f4-ed5a-4305-8172-fdb3f0d173ea,
  abstract     = {Primary infections and vaccination stimulates the immunesystem to produce memory cells that rapidly respond to reexposure of the same antigen. These memory responses are dependent on an adaptive type of immunity that sustains the reactivity of the immune system by long-lived memory immune cells. From an evolutionary perspective adaptive immunity as such appears to be restricted to jawed vertebrates, since non-jawed vertebrates and invertebrates lack recombining receptors and memory responses to infection. One of the two major celltypes of the adaptive immune response is the B-cell. B-cell development is a tightly controlled process that is dependent on the precise transcriptional regulation of intracellular and membrane bound proteins. During the evolutionary transition from non-jawed to jawed vertebrates both the immune systems and the regulatory transcription factors have undergone diversification. One diversified group of transcription factors is the SPI-group of the ETS transcription family, that contains the PU.1, SPI-B, SPI-C and SPI-lamprey proteins. The absence of the PU.1 gene results in a complete block of early B-cell development. SPI-B knock-out mice display reduced ability to terminally differentiate into plasma cells. Both PU.1 and SPI-B activate transcription dependent on acidic domains in the N-terminus of the proteins. Previously it was shown that SPI-C can activate transcription from a kappa-Y Ig light chain promoter element. We scrutinised the SPI-C protein and could map an acidic transactivating region to the N-terminus of the protein. SPI-C, in contrary to SPI-B or PU.1, does not form a ternary complex with PIP on a lambda-B light chain enhancer element in electro-mobility shift assays. In addition, we identified the human version of the SPI-C protein and mapped the human and mouse genes. The human SPI-C was, like the mouse orthologue, expressed in the spleen and B-cell lines but not in T-cells or in the thymus. Phylogenetic analysis shows that human SPI-C is closest related to SPI-C orthologues. In order to identify proteins interacting with the SPI-C transcription factor we employed the yeast two hybrid system. In such a screen we identified a partial STAT6 clone (13:45) as an interactor of SPI-C. To confirm that SPI-C and 13:45 interacted in mammalian cells we coexpressed the proteins in the COS7 cell line and performed co-immunoprecipitations. 13:45 or the full length STAT6 was co-immunoprecipitated with the SPI-C protein. STAT6 binds to the I-epsilon promoter that regulate transcription and class switch recombination to the IgE isotype in a IL-4 dependent manner. STAT6 and SPI-C activates an I-epsilon reporter gene synergistically in an IL-4 dependent manner when ectopically expressed in COS7 cells and may thus regulate the induction of class switch recombination to the IgE isotype and allergy.},
  author       = {Carlsson, Robert},
  isbn         = {91-628-6195-6},
  keyword      = {serology,transplantation,Immunologi,serologi,Immunology,B-lymphocyte,phylogeny,STAT6,SPI-C,transcription},
  language     = {eng},
  pages        = {138},
  publisher    = {Robert Carlsson, BMC I13, 22184, Lund, Sweden,},
  school       = {Lund University},
  title        = {The acidic domain, the human version and the protein interaction of the ETS transcription factor SPI-C},
  year         = {2004},
}