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Themis is a member of a new metazoan gene family and is required for the completion of thymocyte positive selection.

Johnson AL, Aravind L, Shulzhenko N, Morgun A, Choi SY, Crockford TL, Lambe T, Domaschenz H, Kucharska EM, Zheng L, Vinuesa CG, Lenardo MJ, Goodnow CC, Cornall RJ, Schwartz RH - Nat. Immunol. (2009)

Bottom Line: T cell antigen receptor (TCR) signaling in CD4(+)CD8(+) double-positive thymocytes determines cell survival and lineage commitment, but the genetic and molecular basis of this process is poorly defined.Themis contains a tandem repeat of a unique globular domain (called 'CABIT' here) that includes a cysteine motif that defines a family of five uncharacterized vertebrate proteins with orthologs in most animal species.Themis-deficient thymocytes showed no substantial impairment in early TCR signaling but did show altered expression of genes involved in the cell cycle and survival before and during positive selection.

View Article: PubMed Central - PubMed

Affiliation: Nuffield Department of Clinical Medicine, Oxford University, UK.

ABSTRACT
T cell antigen receptor (TCR) signaling in CD4(+)CD8(+) double-positive thymocytes determines cell survival and lineage commitment, but the genetic and molecular basis of this process is poorly defined. To address this issue, we used ethylnitrosourea mutagenesis to identify a previously unknown T lineage-specific gene, Themis, which is critical for the completion of positive selection. Themis contains a tandem repeat of a unique globular domain (called 'CABIT' here) that includes a cysteine motif that defines a family of five uncharacterized vertebrate proteins with orthologs in most animal species. Themis-deficient thymocytes showed no substantial impairment in early TCR signaling but did show altered expression of genes involved in the cell cycle and survival before and during positive selection. Our data suggest a unique function for Themis in sustaining positive selection.

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Induced premature stop codon in the Themis gene (E430004N04Rik) in 5AT161 mutant mice(a) The critical mapping interval of the 5AT161 mutation with the location of key SNPs and microsatellite markers between B6 and 129 or CBA strains. B6 homozygotes (black squares) and heterozygotes (white squares) are shown for affected and unaffected F2 mice along with the number of recombinants (Rec) observed in affected mice for each genetic marker. (b) Sequence trace histograms of the Tyr-489 mutated codon in wild-type and 5AT161 mice. (c) Amino acid sequence alignment of the region surrounding the conserved cysteine residue in the CABIT domain(s) of multiple Themis protein family members. Highly conserved hydrophobic residues (yellow), conserved cysteine residue(s) (red), and putative coiled-coil motif (underlined) are highlighted. In the case of the two domain proteins like Themis itself, the two CABIT domains are indicated by the prefix 1 or 2. The organism abbreviations are: Ccap : Capitella capitata; Dmel : Drosophila melanogaster; Drer : Danio rerio; Hsap : Homo sapiens; Mmus : Mus musculus; Olat : Oryzias latipes.
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Figure 3: Induced premature stop codon in the Themis gene (E430004N04Rik) in 5AT161 mutant mice(a) The critical mapping interval of the 5AT161 mutation with the location of key SNPs and microsatellite markers between B6 and 129 or CBA strains. B6 homozygotes (black squares) and heterozygotes (white squares) are shown for affected and unaffected F2 mice along with the number of recombinants (Rec) observed in affected mice for each genetic marker. (b) Sequence trace histograms of the Tyr-489 mutated codon in wild-type and 5AT161 mice. (c) Amino acid sequence alignment of the region surrounding the conserved cysteine residue in the CABIT domain(s) of multiple Themis protein family members. Highly conserved hydrophobic residues (yellow), conserved cysteine residue(s) (red), and putative coiled-coil motif (underlined) are highlighted. In the case of the two domain proteins like Themis itself, the two CABIT domains are indicated by the prefix 1 or 2. The organism abbreviations are: Ccap : Capitella capitata; Dmel : Drosophila melanogaster; Drer : Danio rerio; Hsap : Homo sapiens; Mmus : Mus musculus; Olat : Oryzias latipes.

Mentions: To identify the mutation responsible for the T cell defect in 5AT161 mice, we screened F2 mice from (5AT161 x 129) and (5AT161 x CBA) intercrosses for a peripheral blood CD4:CD8 ratio of less than 1. As expected for a recessive trait, approximately 25% (34/130) of the F2 mice were affected (Supplementary Fig. 5). Using strain-specific genetic markers, the 5AT161 locus was mapped to a 2.4 Mb region between 27.5 and 29.9 Mb on chromosome 10, which contains10 genes (Fig. 3a). ENU randomly induces a point mutation every 1-2 Mb suggesting that very few mutations would be expected in an interval of this size15. A previously uncharacterized gene in the interval, E430004N04Rik, was a likely candidate based on its T cell-specific expression profile (http://symatlas.gnf.org). We identified a T→A transversion in affected 5AT161 mice that is predicted to generate a stop codon in place of the tyrosine residue at position 489 in the predicted open reading frame (ORF) of E430004N04Rik (Fig. 3b). In a consensus reached among the three laboratories that have recently uncovered the function of this gene, we decided to call it Themis for Thymus Expressed Molecule Involved in Selection16,17.


Themis is a member of a new metazoan gene family and is required for the completion of thymocyte positive selection.

Johnson AL, Aravind L, Shulzhenko N, Morgun A, Choi SY, Crockford TL, Lambe T, Domaschenz H, Kucharska EM, Zheng L, Vinuesa CG, Lenardo MJ, Goodnow CC, Cornall RJ, Schwartz RH - Nat. Immunol. (2009)

Induced premature stop codon in the Themis gene (E430004N04Rik) in 5AT161 mutant mice(a) The critical mapping interval of the 5AT161 mutation with the location of key SNPs and microsatellite markers between B6 and 129 or CBA strains. B6 homozygotes (black squares) and heterozygotes (white squares) are shown for affected and unaffected F2 mice along with the number of recombinants (Rec) observed in affected mice for each genetic marker. (b) Sequence trace histograms of the Tyr-489 mutated codon in wild-type and 5AT161 mice. (c) Amino acid sequence alignment of the region surrounding the conserved cysteine residue in the CABIT domain(s) of multiple Themis protein family members. Highly conserved hydrophobic residues (yellow), conserved cysteine residue(s) (red), and putative coiled-coil motif (underlined) are highlighted. In the case of the two domain proteins like Themis itself, the two CABIT domains are indicated by the prefix 1 or 2. The organism abbreviations are: Ccap : Capitella capitata; Dmel : Drosophila melanogaster; Drer : Danio rerio; Hsap : Homo sapiens; Mmus : Mus musculus; Olat : Oryzias latipes.
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Related In: Results  -  Collection

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Figure 3: Induced premature stop codon in the Themis gene (E430004N04Rik) in 5AT161 mutant mice(a) The critical mapping interval of the 5AT161 mutation with the location of key SNPs and microsatellite markers between B6 and 129 or CBA strains. B6 homozygotes (black squares) and heterozygotes (white squares) are shown for affected and unaffected F2 mice along with the number of recombinants (Rec) observed in affected mice for each genetic marker. (b) Sequence trace histograms of the Tyr-489 mutated codon in wild-type and 5AT161 mice. (c) Amino acid sequence alignment of the region surrounding the conserved cysteine residue in the CABIT domain(s) of multiple Themis protein family members. Highly conserved hydrophobic residues (yellow), conserved cysteine residue(s) (red), and putative coiled-coil motif (underlined) are highlighted. In the case of the two domain proteins like Themis itself, the two CABIT domains are indicated by the prefix 1 or 2. The organism abbreviations are: Ccap : Capitella capitata; Dmel : Drosophila melanogaster; Drer : Danio rerio; Hsap : Homo sapiens; Mmus : Mus musculus; Olat : Oryzias latipes.
Mentions: To identify the mutation responsible for the T cell defect in 5AT161 mice, we screened F2 mice from (5AT161 x 129) and (5AT161 x CBA) intercrosses for a peripheral blood CD4:CD8 ratio of less than 1. As expected for a recessive trait, approximately 25% (34/130) of the F2 mice were affected (Supplementary Fig. 5). Using strain-specific genetic markers, the 5AT161 locus was mapped to a 2.4 Mb region between 27.5 and 29.9 Mb on chromosome 10, which contains10 genes (Fig. 3a). ENU randomly induces a point mutation every 1-2 Mb suggesting that very few mutations would be expected in an interval of this size15. A previously uncharacterized gene in the interval, E430004N04Rik, was a likely candidate based on its T cell-specific expression profile (http://symatlas.gnf.org). We identified a T→A transversion in affected 5AT161 mice that is predicted to generate a stop codon in place of the tyrosine residue at position 489 in the predicted open reading frame (ORF) of E430004N04Rik (Fig. 3b). In a consensus reached among the three laboratories that have recently uncovered the function of this gene, we decided to call it Themis for Thymus Expressed Molecule Involved in Selection16,17.

Bottom Line: T cell antigen receptor (TCR) signaling in CD4(+)CD8(+) double-positive thymocytes determines cell survival and lineage commitment, but the genetic and molecular basis of this process is poorly defined.Themis contains a tandem repeat of a unique globular domain (called 'CABIT' here) that includes a cysteine motif that defines a family of five uncharacterized vertebrate proteins with orthologs in most animal species.Themis-deficient thymocytes showed no substantial impairment in early TCR signaling but did show altered expression of genes involved in the cell cycle and survival before and during positive selection.

View Article: PubMed Central - PubMed

Affiliation: Nuffield Department of Clinical Medicine, Oxford University, UK.

ABSTRACT
T cell antigen receptor (TCR) signaling in CD4(+)CD8(+) double-positive thymocytes determines cell survival and lineage commitment, but the genetic and molecular basis of this process is poorly defined. To address this issue, we used ethylnitrosourea mutagenesis to identify a previously unknown T lineage-specific gene, Themis, which is critical for the completion of positive selection. Themis contains a tandem repeat of a unique globular domain (called 'CABIT' here) that includes a cysteine motif that defines a family of five uncharacterized vertebrate proteins with orthologs in most animal species. Themis-deficient thymocytes showed no substantial impairment in early TCR signaling but did show altered expression of genes involved in the cell cycle and survival before and during positive selection. Our data suggest a unique function for Themis in sustaining positive selection.

Show MeSH