|Coordinate||5,772,455 bp (GRCm38)|
|Base Change||T ⇒ A (forward strand)|
|Gene Name||zinc finger E-box binding homeobox 1|
|Synonym(s)||3110032K11Rik, Tw, MEB1, Zfhx1a, Zfhep, ZEB, AREB6, Zfx1a, Tcf18, Nil2, Tcf8, [delta]EF1|
|Chromosomal Location||5,591,860-5,775,467 bp (+)|
|MGI Phenotype||Mutations at this locus affect thymus organization and homozygotes exhibit severe thymic T cell deficiency. Some mutations also exhibit extensive skeletal abnormalities. Homozygotes generally die at birth.|
|Amino Acid Change||Cysteine changed to Serine|
|Institutional Source||Beutler Lab|
|Gene Model||not available|
AA Change: C915S
|Predicted Effect||probably damaging
PolyPhen 2 Score 0.998 (Sensitivity: 0.27; Specificity: 0.99)
|Phenotypic Category||T-dependent humoral response defect- decreased antibody response to rSFV|
|Alleles Listed at MGI|
|Mode of Inheritance||Autosomal Recessive|
|Local Stock||Live Mice|
|Last Updated||05/13/2016 3:09 PM by Anne Murray|
|Record Created||07/06/2013 4:18 PM by Kuan-Wen Wang|
The serpens phenotype was identified among G3 mice of the pedigree R0445, some of which showed a diminished T-dependent antibody response to recombinant Semliki Forest virus (rSFV)-encoded β-galactosidase (rSFV-β-gal) (Figure 1).
|Nature of Mutation|
Whole exome HiSeq sequencing of the G1 grandsire identified 53 mutations. The diminished T-dependent antibody response was linked by continuous variable mapping to a mutation in Zeb1: a T to A transversion at base pair 5,772,455 (v38) on chromosome 18, or base pair 180,596 in the GenBank genomic region NC_000084. Linkage was found with a recessive model of inheritance, wherein 1 variant homozygote departed phenotypically from 5 homozygous reference mice and 10 heterozygous mice with a P value of 8.436 x 10-6 (Figure 2).
The mutation corresponds to residue 2,793 in the mRNA sequence NM_011546 within exon 8 of 8 total exons.
The mutated nucleotide is indicated in red. The mutation results in a cysteine (C) to serine (S) substitution at position 915 (C915S) in the ZEB1 protein, and is strongly predicted by Polyphen-2 to cause loss of function (score = 0.998) (1).
Zeb1 and Zeb2 form the mammalian Zeb family of transcription factors. Zeb1 contains seven C2H2-type zinc finger domains, each approximately 23 amino acids in length (2-5) (Figure 3). Four are clustered near the N-terminus (NZF, spanning aa 150-272) and three near the C-terminus (CZF, spanning aa 882-959). Near the center of the protein is a homeobox domain (aa 559-618). Repressor domains have been identified at the N-terminus (aa 19-127) (6), in a large central region between the two zinc finger clusters (aa 303-902) (7), and in two separate regions within aa 303-902 (aa 302-542 and 760-902) (8). The region between the CZF domain and the C terminus is highly rich in glutamic acid residues (38%), and has been characterized as an activation domain (aa 1011-1124) (9). Three five-amino acid sequences (PLNLC, PLDLS, PLNLS) between the homeodomain and the CZF domain bind to the co-repressor CtBP, and this region (spanning aa 685-749) is designated the CtBP interaction domain (CID) (10). A region between the NZF and homeobox domains of Zeb1 was identified as a Smad interaction domain (aa 377-456) for Smad1, Smad2, and Smad3 (11). Zeb1 synergizes with TGF-β/BMP in transcriptional activation by aiding in the recruitment of p300 and P/CAF (histone acetylases) through a direct interaction involving the N-terminal region of Zeb1 (12). The negative cofactor NC2 binds to amino acids 726-829 of Zeb1 (9).
The serpens mutation results in a cysteine to serine substitution at amino acid 915 within the CZF domain.
Please see the record cellophane for more information about Zeb1.
Mice with a truncation of the C terminus of Zeb1 following amino acid 727 (Zeb1ΔC727/ΔC727), and therefore lacking the cluster of C-terminal zinc fingers and the Glu-rich domain, exhibited lethality within two days after birth (13). Like those of Zeb1-/- mice, thymi of surviving Zeb1ΔC727/ΔC727 mice were smaller and contained 0.2% to 1% the number of thymocytes found in wild type mice (13). The medulla and cortex were indistinguishable upon histological analysis of Zeb1ΔC727/ΔC727 thymus sections. Spleen size and cellularity were similar between Zeb1ΔC727/ΔC727 and wild type mice, although there was a trend toward reduced cellularity in Zeb1ΔC727/ΔC727 mice. Lymph node cellularity was 10% of that in wild type mice. The ENU-induced mutant mice, termed cellophane, exhibited reduced B cell proliferation in response to BCR crosslinking (14). The reduced ability of cellophane B cells to proliferate in response to BCR stimulation is proposed to lead to impaired antibody responses and germinal center formation following immunization. Similar to cellophane mice, the serpens mice also exhibited impaired antibody responses to the T-dependent antigen, indicating reduced function of Zeb1serpens.
serpens(F):5'- TGGCCTCATCTGCAAAGCAGTG -3'
serpens(R):5'- AACATGCTCAGTCGCCAGGACTTC -3'
serpens_seq(F):5'- CTGCAAAGCAGTGTATAACCTTG -3'
serpens_seq(R):5'- GACTTCCGGCAGGACTTC -3'
1. Adzhubei, I. A., Schmidt, S., Peshkin, L., Ramensky, V. E., Gerasimova, A., Bork, P., Kondrashov, A. S., and Sunyaev, S. R. (2010) A Method and Server for Predicting Damaging Missense Mutations. Nat Methods. 7, 248-249.
2. Funahashi, J., Sekido, R., Murai, K., Kamachi, Y., and Kondoh, H. (1993) Delta-Crystallin Enhancer Binding Protein Delta EF1 is a Zinc Finger-Homeodomain Protein Implicated in Postgastrulation Embryogenesis. Development. 119, 433-446.
3. Fortini, M. E., Lai, Z. C., and Rubin, G. M. (1991) The Drosophila Zfh-1 and Zfh-2 Genes Encode Novel Proteins Containing both Zinc-Finger and Homeodomain Motifs. Mech Dev. 34, 113-122.
4. Genetta, T., and Kadesch, T. (1996) Cloning of a cDNA Encoding a Mouse Transcriptional Repressor Displaying Striking Sequence Conservation Across Vertebrates. Gene. 169, 289-290.
5. Genetta, T., Ruezinsky, D., and Kadesch, T. (1994) Displacement of an E-Box-Binding Repressor by Basic Helix-Loop-Helix Proteins: Implications for B-Cell Specificity of the Immunoglobulin Heavy-Chain Enhancer. Mol Cell Biol. 14, 6153-6163.
6. Sekido, R., Murai, K., Kamachi, Y., and Kondoh, H. (1997) Two Mechanisms in the Action of Repressor deltaEF1: Binding Site Competition with an Activator and Active Repression. Genes Cells. 2, 771-783.
7. Postigo, A. A., and Dean, D. C. (1997) ZEB, a Vertebrate Homolog of Drosophila Zfh-1, is a Negative Regulator of Muscle Differentiation. EMBO J. 16, 3935-3943.
8. Postigo, A. A., and Dean, D. C. (1999) Independent Repressor Domains in ZEB Regulate Muscle and T-Cell Differentiation. Mol Cell Biol. 19, 7961-7971.
9. Ikeda, K., Halle, J. P., Stelzer, G., Meisterernst, M., and Kawakami, K. (1998) Involvement of Negative Cofactor NC2 in Active Repression by Zinc Finger-Homeodomain Transcription Factor AREB6. Mol Cell Biol. 18, 10-18.
10. Postigo, A. A., and Dean, D. C. (1999) ZEB Represses Transcription through Interaction with the Corepressor CtBP. Proc Natl Acad Sci U S A. 96, 6683-6688.
11. Postigo, A. A. (2003) Opposing Functions of ZEB Proteins in the Regulation of the TGFbeta/BMP Signaling Pathway. EMBO J. 22, 2443-2452.
12. Postigo, A. A., Depp, J. L., Taylor, J. J., and Kroll, K. L. (2003) Regulation of Smad Signaling through a Differential Recruitment of Coactivators and Corepressors by ZEB Proteins. EMBO J. 22, 2453-2462.
13. Higashi, Y., Moribe, H., Takagi, T., Sekido, R., Kawakami, K., Kikutani, H., and Kondoh, H. (1997) Impairment of T Cell Development in deltaEF1 Mutant Mice. J Exp Med. 185, 1467-1479.
|Science Writers||Anne Murray|
|Authors||Kuan-Wen Wang, Jin Huk Choi, Ming Zeng, Bruce Beutler|