Phenotypic Mutation 'Star_lord' (pdf version)
AlleleStar_lord
Mutation Type missense
Chromosome11
Coordinate11,719,448 bp (GRCm39)
Base Change T ⇒ A (forward strand)
Gene Ikzf1
Gene Name IKAROS family zinc finger 1
Synonym(s) Zfpn1a1, 5832432G11Rik, LyF-1, Ikaros
Chromosomal Location 11,634,980-11,722,926 bp (+) (GRCm39)
MGI Phenotype FUNCTION: The protein encoded by this gene belongs to a family of transcription factors that are characterized by a set of four DNA-binding zinc fingers at the N-terminus and two C-terminal zinc fingers involved in protein dimerization. It is regulated by both epigenetic and transcription factors. This protein is a transcriptional regulator of hematopoietic cell development and homeostasis. In addition, it is required to confer temporal competence to retinal progenitor cells during embryogenesis, demonstrating an essential function in nervous system development. Alternative splicing results in multiple transcript variants encoding different isoforms. [provided by RefSeq, Sep 2014]
PHENOTYPE: Homozygous mutants have a variety of T, B, and hematopoeitic cell maturation defects. Heterozygotes for one allele exhibit dominant negative effects and mice develop lymphoproliferative disorders. [provided by MGI curators]
Accession Number

NCBI RefSeq: NM_001025597 (variant 1), NM_009578 (variant 2), NM_001301863 (variant 3), NM_001301865 (variant 4), NM_001301866 (variant 5), NM_001301868 (variant 6); MGI:1342540

MappedYes 
Amino Acid Change Methionine changed to Lysine
Institutional SourceBeutler Lab
Gene Model predicted gene model for protein(s): [ENSMUSP00000018798] [ENSMUSP00000067372] [ENSMUSP00000075992]
AlphaFold no structure available at present
SMART Domains Protein: ENSMUSP00000018798
Gene: ENSMUSG00000018654
AA Change: M385K

DomainStartEndE-ValueType
ZnF_C2H2 58 80 8.02e-5 SMART
ZnF_C2H2 86 108 2.57e-3 SMART
ZnF_C2H2 114 137 8.22e-2 SMART
low complexity region 282 293 N/A INTRINSIC
ZnF_C2H2 371 393 7.49e0 SMART
ZnF_C2H2 399 423 5.34e-1 SMART
Predicted Effect probably damaging

PolyPhen 2 Score 0.987 (Sensitivity: 0.73; Specificity: 0.96)
(Using ENSMUST00000018798)
SMART Domains Protein: ENSMUSP00000067372
Gene: ENSMUSG00000018654
AA Change: M492K

DomainStartEndE-ValueType
ZnF_C2H2 137 159 1.43e-1 SMART
ZnF_C2H2 165 187 8.02e-5 SMART
ZnF_C2H2 193 215 2.57e-3 SMART
ZnF_C2H2 221 244 8.22e-2 SMART
low complexity region 389 400 N/A INTRINSIC
ZnF_C2H2 478 500 7.49e0 SMART
ZnF_C2H2 506 530 5.34e-1 SMART
Predicted Effect probably damaging

PolyPhen 2 Score 0.999 (Sensitivity: 0.14; Specificity: 0.99)
(Using ENSMUST00000065433)
SMART Domains Protein: ENSMUSP00000075992
Gene: ENSMUSG00000018654
AA Change: M472K

DomainStartEndE-ValueType
ZnF_C2H2 117 139 1.43e-1 SMART
ZnF_C2H2 145 167 8.02e-5 SMART
ZnF_C2H2 173 195 2.57e-3 SMART
ZnF_C2H2 201 224 8.22e-2 SMART
low complexity region 369 380 N/A INTRINSIC
ZnF_C2H2 458 480 7.49e0 SMART
ZnF_C2H2 486 510 5.34e-1 SMART
Predicted Effect probably damaging

PolyPhen 2 Score 0.994 (Sensitivity: 0.69; Specificity: 0.97)
(Using ENSMUST00000076700)
Meta Mutation Damage Score 0.9625 question?
Is this an essential gene? Non Essential (E-score: 0.000) question?
Phenotypic Category Autosomal Dominant
Candidate Explorer Status loading ...
Single pedigree
Linkage Analysis Data
Penetrance  
Alleles Listed at MGI

All Mutations and Alleles(14) : Chemically induced (ENU)(1) Gene trapped(1) Targeted(12)

Lab Alleles
AlleleSourceChrCoordTypePredicted EffectPPH Score
IGL01302:Ikzf1 APN 11 11718923 missense probably damaging 1.00
IGL01367:Ikzf1 APN 11 11698358 missense probably benign 0.04
IGL01823:Ikzf1 APN 11 11719091 missense possibly damaging 0.64
IGL02342:Ikzf1 APN 11 11650216 utr 5 prime probably benign
IGL02452:Ikzf1 APN 11 11698545 missense probably damaging 1.00
IGL03209:Ikzf1 APN 11 11650226 missense probably benign
IGL03236:Ikzf1 APN 11 11657848 missense probably damaging 1.00
Herrscher UTSW 11 11718961 nonsense probably null
waxwing UTSW 11 11698464 nonsense probably null
R0133:Ikzf1 UTSW 11 11691015 splice site probably null
R0417:Ikzf1 UTSW 11 11719352 missense probably benign 0.19
R0633:Ikzf1 UTSW 11 11719223 missense probably damaging 1.00
R0734:Ikzf1 UTSW 11 11708195 missense probably damaging 1.00
R1693:Ikzf1 UTSW 11 11657838 missense probably damaging 1.00
R2114:Ikzf1 UTSW 11 11719473 missense probably damaging 1.00
R2927:Ikzf1 UTSW 11 11719324 missense probably damaging 1.00
R4250:Ikzf1 UTSW 11 11704166 missense probably damaging 1.00
R5156:Ikzf1 UTSW 11 11719448 missense probably damaging 1.00
R5912:Ikzf1 UTSW 11 11698464 nonsense probably null
R6274:Ikzf1 UTSW 11 11718961 nonsense probably null
R7614:Ikzf1 UTSW 11 11719019 missense probably damaging 1.00
R7727:Ikzf1 UTSW 11 11698339 missense probably damaging 1.00
R7759:Ikzf1 UTSW 11 11719256 missense probably damaging 0.98
R8758:Ikzf1 UTSW 11 11711359 missense probably benign 0.03
R8946:Ikzf1 UTSW 11 11719485 missense possibly damaging 0.86
R8998:Ikzf1 UTSW 11 11635013 start gained probably benign
R8999:Ikzf1 UTSW 11 11635013 start gained probably benign
R9624:Ikzf1 UTSW 11 11719219 missense probably damaging 1.00
Z1176:Ikzf1 UTSW 11 11708194 critical splice acceptor site probably null
Mode of Inheritance Autosomal Dominant
Local Stock
Repository
Last Updated 2019-09-04 9:40 PM by Diantha La Vine
Record Created 2017-05-11 12:54 PM
Record Posted 2018-08-22
Phenotypic Description

Figure 1. Star_lord mice exhibited reduced heart rates on day 3 of testing. Normalized data are shown. Abbreviations: WT, wild-type; REF, homozygous reference mice; HET, heterozygous variant mice; VAR, homozygous variant mice. Mean (μ) and standard deviation (σ) are indicated.

Figure 2. Star_lord mice exhibited reduced average heart rates. Normalized data are shown. Abbreviations: WT, wild-type; REF, homozygous reference mice; HET, heterozygous variant mice; VAR, homozygous variant mice. Mean (μ) and standard deviation (σ) are indicated.

Figure 3. Star_lord mice exhibit increased T-dependent IgG responses to ovalbumin administered with aluminum hydroxide. IgG levels were determined by ELISA. Normalized data are shown. Abbreviations: WT, wild-type; REF, homozygous reference mice; HET, heterozygous variant mice; VAR, homozygous variant mice. Mean (μ) and standard deviation (σ) are indicated.

Figure 4. Star_lord mice exhibit reduced B to T cell ratios. Flow cytometric analysis of peripheral blood was utilized to determine B and T cell frequencies. Normalized data are shown. Abbreviations: WT, wild-type; REF, homozygous reference mice; HET, heterozygous variant mice; VAR, homozygous variant mice. Mean (μ) and standard deviation (σ) are indicated.
Figure 5. Star_lord mice exhibit reduced CD4 to CD8 T cell ratios. Flow cytometric analysis of peripheral blood was utilized to determine T cell frequencies. Normalized data are shown. Abbreviations: WT, wild-type; REF, homozygous reference mice; HET, heterozygous variant mice; VAR, homozygous variant mice. Mean (μ) and standard deviation (σ) are indicated.

Figure 6. Star_lord mice exhibit decreased frequencies of peripheral CD4+ T cells in CD3+ T cells. Flow cytometric analysis of peripheral blood was utilized to determine T cell frequency. Normalized data are shown. Abbreviations: WT, wild-type; REF, homozygous reference mice; HET, heterozygous variant mice; VAR, homozygous variant mice. Mean (μ) and standard deviation (σ) are indicated.

Figure 7. Star_lord mice exhibit decreased frequencies of peripheral naive CD4+ T cells in CD4+ T cells. Flow cytometric analysis of peripheral blood was utilized to determine T cell frequency. Normalized data are shown. Abbreviations: WT, wild-type; REF, homozygous reference mice; HET, heterozygous variant mice; VAR, homozygous variant mice. Mean (μ) and standard deviation (σ) are indicated.
Figure 8. Star_lord mice exhibit decreased frequencies of peripheral naive CD8+ T cells in CD8+ T cells. Flow cytometric analysis of peripheral blood was utilized to determine T cell frequency. Normalized data are shown. Abbreviations: WT, wild-type; REF, homozygous reference mice; HET, heterozygous variant mice; VAR, homozygous variant mice. Mean (μ) and standard deviation (σ) are indicated.
Figure 9. Star_lord mice exhibit increased frequencies of peripheral T cells. Flow cytometric analysis of peripheral blood was utilized to determine T cell frequency. Normalized data are shown. Abbreviations: WT, wild-type; REF, homozygous reference mice; HET, heterozygous variant mice; VAR, homozygous variant mice. Mean (μ) and standard deviation (σ) are indicated.
Figure 10. Star_lord mice exhibit increased frequencies of peripheral CD44+ CD4 T cells. Flow cytometric analysis of peripheral blood was utilized to determine T cell frequency. Normalized data are shown. Abbreviations: WT, wild-type; REF, homozygous reference mice; HET, heterozygous variant mice; VAR, homozygous variant mice. Mean (μ) and standard deviation (σ) are indicated.
Figure 11. Star_lord mice exhibit increased frequencies of peripheral CD8+ T cells. Flow cytometric analysis of peripheral blood was utilized to determine T cell frequency. Normalized data are shown. Abbreviations: WT, wild-type; REF, homozygous reference mice; HET, heterozygous variant mice; VAR, homozygous variant mice. Mean (μ) and standard deviation (σ) are indicated.
Figure 12. Star_lord mice exhibit increased frequencies of peripheral CD8+ T cells in CD3+ T cells. Flow cytometric analysis of peripheral blood was utilized to determine T cell frequency. Normalized data are shown. Abbreviations: WT, wild-type; REF, homozygous reference mice; HET, heterozygous variant mice; VAR, homozygous variant mice. Mean (μ) and standard deviation (σ) are indicated.
Figure 13. Star_lord mice exhibit increased frequencies of peripheral central memory CD4 T cells in CD4 T cells. Flow cytometric analysis of peripheral blood was utilized to determine T cell frequency. Normalized data are shown. Abbreviations: WT, wild-type; REF, homozygous reference mice; HET, heterozygous variant mice; VAR, homozygous variant mice. Mean (μ) and standard deviation (σ) are indicated.
Figure 14. Star_lord mice exhibit increased frequencies of peripheral central memory CD8 T cells in CD8 T cells. Flow cytometric analysis of peripheral blood was utilized to determine T cell frequency. Normalized data are shown. Abbreviations: WT, wild-type; REF, homozygous reference mice; HET, heterozygous variant mice; VAR, homozygous variant mice. Mean (μ) and standard deviation (σ) are indicated.
Figure 15. Star_lord mice exhibit increased frequencies of peripheral effector memory CD4 T cells in CD4 T cells. Flow cytometric analysis of peripheral blood was utilized to determine T cell frequency. Normalized data are shown. Abbreviations: WT, wild-type; REF, homozygous reference mice; HET, heterozygous variant mice; VAR, homozygous variant mice. Mean (μ) and standard deviation (σ) are indicated.
Figure 16. Star_lord mice exhibit increased frequencies of peripheral B1 cells. Flow cytometric analysis of peripheral blood was utilized to determine B1 cell frequency. Normalized data are shown. Abbreviations: WT, wild-type; REF, homozygous reference mice; HET, heterozygous variant mice; VAR, homozygous variant mice. Mean (μ) and standard deviation (σ) are indicated.
Figure 17. Star_lord mice exhibit increased expression of CD44 on peripheral blood CD8 T cells. Flow cytometric analysis of peripheral blood was utilized to determine CD44 MFI. Normalized data are shown. Abbreviations: WT, wild-type; REF, homozygous reference mice; HET, heterozygous variant mice; VAR, homozygous variant mice. Mean (μ) and standard deviation (σ) are indicated.
Figure 18. Star_lord mice exhibit diminished NK cell-associated cytotoxicity. Normalized data are shown. Abbreviations: WT, wild-type; REF, homozygous reference mice; HET, heterozygous variant mice; VAR, homozygous variant mice. Mean (μ) and standard deviation (σ) are indicated.

The Star_lord phenotype was identified among N-ethyl-N-nitrosourea (ENU)-mutagenized G3 mice of the pedigree R5156, some of which showed reduced heart rates on day 3 of testing (Figure 1) as well as reduced average heart rates (Figure 2) compared to wild-type littermates. Some mice also showed increased T-dependent antibody responses to ovalbumin administered with aluminum hydroxide (Figure 3). The mice showed reduced B to T cell ratios (Figure 4) and reduced CD4 to CD8 T cell ratios (Figure 5) as well as reduced frequencies of CD4+ T cells in CD3+ T cells (Figure 6), naïve CD4 T cells in CD4 T cells (Figure 7), and naïve CD8 T cells in CD8 T cells (Figure 8) with concomitant increased frequencies of T cells (Figure 9), CD44+ CD4 T cells (Figure 10), CD8+ T cells (Figure 11), CD8+ T cells in CD3+ T cells (Figure 12), central memory CD4 T cells in CD4 T cells (Figure 13), central memory CD8 T cells in CD8 T cells (Figure 14), effector memory CD4 T cells in CD4 T cells (Figure 15), and B1 cells (Figure 16), all in the peripheral blood. The expression of CD44 on peripheral blood CD8 T cells was increased (Figure 17). The mice also showed diminished NK cell-associated cytotoxicity (Figure 18).

Nature of Mutation

Figure 19. Linkage mapping of the increased CD8+ T cell in CD3+ T cell frequency using a dominant model of inheritance. Manhattan plot shows -log10 P values (Y-axis) plotted against the chromosome positions of 55 mutations (X-axis) identified in the G1 male of pedigree R5156. Normalized phenotype data are shown for single locus linkage analysis without consideration of G2 dam identity. Horizontal pink and red lines represent thresholds of P = 0.05, and the threshold for P = 0.05 after applying Bonferroni correction, respectively.

Whole exome HiSeq sequencing of the G1 grandsire identified 55 mutations. All of the above anomalies were linked by continuous variable mapping to a mutation in Ikzf1: a T to A transversion at base pair 11,769,448 (v38) on chromosome 11, or base pair 84,479 in the GenBank genomic region NC_000077 encoding Ikzf1. The strongest association was found with a additive/dominant model of inheritance to the increased CD8+ T cell in CD3+ T cell frequency, wherein 27 heterozygous mice departed phenotypically from 29 homozygous reference mice with a P value of 1.655 x 10-16 (Figure 19); pedigree R5156 did not have any variant homozygous mice.  

The mutation corresponds to residue 1,972 in the mRNA sequence NM_001025597 within exon 8 of 8 total exons and to residue 1,711 in the mRNA sequence NM_009578 within exon 7 of 7 total exons.

84464 TTCCTGGATCACGTCATGTATACCATTCACATG
467   -F--L--D--H--V--M--Y--T--I--H--M- (variants 1, 3, and 6)
380   -F--L--D--H--V--M--Y--T--I--H--M- (variants 2, 4, and 5)
 

Genomic numbering corresponds to NC_000077. The mutated nucleotide is indicated in red. The mutation results in a methionine to lysine substitution at amino acid 472 (M472K) in variant 1 of the IKZF1 protein and a M385K substitution in variant 2 of the IKZF1 protein, and is strongly predicted by PolyPhen-2 to be damaging (score = 0.994, variant 1; score = 0.987, variant 2).

Illustration of Mutations in
Gene & Protein
Protein Prediction
Figure 20. Domain organization of IKAROS. IKAROS has six C2H2-type zinc fingers, with four at the N-terminus and two at the C-terminus. The star_lord mutation results in a methionine to lysine substitution at amino acid 472 in variant 1 of the protein. Other mutations found in the IKAROS protein are shown in red. Click on each mutation for more information.

Ikzf1 (IKAROS family zinc finger 1) encodes IKAROS (alternatively, IK1). IKAROS is a member of the IKAROS family of zinc finger transcription factors, which also includes HELIOS (IKZF2), AIOLOS (IKZF3), EOS (IKZF4), and PEGASUS (IKZF5).

IKAROS has six C2H2-type zinc fingers, with four at the N-terminus and two at the C-terminus (Figure 20) (1). The N-terminal zinc fingers mediate binding to the core DNA motif A/GGGAA in target genes. The C-terminal zinc fingers mediate IKAROS homodimerization as well as IKAROS heterodimerization with other members of the IKAROS protein family (2). Dimerization of the IKAROS proteins enhances their DNA affinity and transcriptional activity.

IKAROS is phosphorylated by casein kinase II on several serine and threonine residues. IKAROS phosphorylation reduces its DNA-binding activity (3;4). Protein phosphatase-1-mediated dephosphorylation of IKAROS restores IKAROS activity (3). BTK- and SYK (see the record for poppy)-mediated phosphorylation of serines near the IKAROS DNA-binding domain promotes IKAROS nuclear localization and DNA binding activity (5;6). In the nucleus, IKAROS is SUMOylated, which interferes with transcriptional repression (7;8). Ubiquitination of IKAROS promotes its proteasomal degradation (3).

Alternative splicing of IKZF1 produces several IKAROS variants [Table 1; reviewed in (9)]. The protein variants differ in the number of N-terminal zinc fingers. Several of the variants can function as dominant-negative versions of IKAROS. For example, the IK6 variant lacks exons 4 to 7, which encode the four N-terminal zinc fingers. IK6 is able to interact with full-length IKAROS proteins, but lacks DNA binding activity.

Table 1. The IKZF1 splice variants

Variant

Splice variant (cDNA) description

Protein description

IK1

Canonical full-length isoform

Canonical full-length isoform

IK2

Lacks exon 4

Lacks the first zinc finger

IK2A

Lacks exon 4 and 7

Lacks the first zinc finger

IK3

Lacks exon 6 and 7

Lacks the fourth zinc finger

IK4

Lacks exons 4 and 6, but retains exon 5

Lacks the first and fourth zinc fingers

IK4A

Lacks exon 4, 6, and 7

Lacks the first and fourth zinc fingers

IK5*

Lacks exons 5 through 7

Lacks the second through fourth zinc fingers

IK6*

Lacks exons 4 through 7

Lacks first four zinc fingers

IK7*

Lacks exons 4 and 5

Lacks the first through third zinc fingers

IK8*

Lacks exons 4 through 6

Lacks the first four zinc fingers

IK9*

Lacks exons 3 through 7

Lacks first four zinc fingers

IKX

Lacks exon 6

Lacks the fourth zinc finger

* isoforms are dominant negative

The star_lord mutation results in a methionine to lysine substitution at amino acid 472 (M472K) in variant 1 of the IKZF1 protein; Met472 is within the fifth zinc finger.

Expression/Localization

IKAROS is expressed during early embryonic hematopoiesis in mice (10;11). IKAROS is also expressed in erythroid and myeloid precursors (12). In the adult, IKAROS is expressed in the spleen, thymus, and peripheral blood leukocytes (1;10;11).

Background

Figure 21. IKAROS functions in hematopoietic cell-fate decisions. The broad stages of hematopoietic stem cell (HSC) development are shown. HSCs differentiate into common myeloid precursors (CMP) and chronic lymphoid precursors (CLP). The CMP generate granulocyte/macrophage precursors that yield granulocytes, monocyte/macrophages, and osteoclasts. The CMPs also generate megakaryocyte/erythroid precursors that yield megakaryocytes, platelets, and erythroid cells. The CLP generate T cell precursors that produce three types of T Helper cells (Th1, 2, & 17) and regulatory T cells (Tregs), B cell precursors that produce memory and plasma cells, as well as Natural Killer (NK) cells. The roles of IKAROS in the regulation of fate decisions are indicated.

Hematopoietic stem cells (HSCs) give rise to multipotent progenitors, which branch into myeloid and lymphoid lineages (Figure 21). The myeloid lineage starts with the common myeloid progenitor (CMP), which gives rise to the megakaryocyte-erythroid progenitors, granulocyte-macrophage progenitors, or early T-cell progenitors. In the lymphoid lineage, common lymphoid progenitors (CLPs) are divided into Ly6D-negative all-lymphoid progenitors (ALPs) and Ly6D-positive B cell biased lymphoid progenitors (BLPs) (13). The ALPs generate B cells, T cells, natural killer cells, and lymphoid dendritic cells, while the BLPs are biased towards the B cell lineage.

IKAROS is a transcription factor that regulates the expression of genes that mediate the production of blood and immune cells, promotes precursor self-renewal, CLP generation from HSCs, B and NK cell lineages from CLPs, inhibition of CMP differentiation, neutrophil generation from granulocyte-macrophage progenitors, and generation of erythroid cells from megakaryocyte-erythroid progenitors [Table 2; reviewed in (14)].

Table 2. Select IKAROS target genes

Target function

Target genes

References

Antigen receptor and recombination machinery

Dntt

(15;16)

Rag1 (see the record for maladaptive)

(17)

Rag2 (see the record for snowcock)

Cd79b (see the record for hallasan)

(18)

Pre-B-cell receptor signaling, cell survival, stromal-cell adhesion and B-cell commitment during pre-B-cell differentiation

Pax5 (see the record for glacier)

(18-20)

Foxo1

Ebf1 (see the record for crater_lake)

Signal transducers and cell surface receptors in B- and T-cell differentiation

Kit (see the record for pretty2)

(20)

Flt3 (see the record for warmflash)

Cd79b

Notch1 (see the record for Antero)

Btla (see the record for Enigmatic)

Clnk

Ltb

Ccr9

Il7r

Cd8a (see the record for alfalfa)

(21)

Tbx21 (see the record for plateau)

(22;23)

Cell adhesion

Ctnnd1

(24)

Fak

(25)

Itga5

(26)

Chromatin remodelers and transcription regulators

Satb1

(27)

Mef2c

Runx2

Sox4

Foxp1 (see the record for foxy)

Hdac9

Ets1

IKAROS regulates lymphocyte differentiation and function by promoting chromatin remodeling (10;12;28-33). IKAROS associates with the nucleosome remodeling and deacetylase complex (termed the NuRD complex), which includes histone deacetylases HDAC1 and HDAC2 as well as the ATP-dependent chromatin remodeling proteins CHD3 and CHD4 (alternatively, Mi-2β). MTA1, MTA2, MBD3, and Rbp46/48 are also components of the NuRD complex (34). IKAROS also associates with polycomb repressive complex-2, which promotes histone H3 lysine 27 trimethylation to maintain genes in an inactive state (35;36). The transcriptional co-factors CtBP, CtIP, and SW/SNF-related complex also can associate with IKAROS (37-39). IKAROS also may directly regulate transcription by interaction with the general transcription factors TFIIB and TBP (40). IKAROS also functions in transcription elongation (3). IKAROS promotes the transfer of protein phosphatase 1α to CDK9, which activates positive transcription elongation factor b and subsequent transcription elongation of IKAROS target genes (3). IKAROS also functions in chromatin accessibility during immunoglobulin gene rearrangement and allelic exclusion at the Igk locus (17;20).

Mutations in IKZF1 are associated with common variable immunodeficiency-13 (OMIM: #616873) (32;33). Patients with common variable immunodeficiency-13 exhibit recurrent bacterial infections, hypogammaglobulinemia, and decreased numbers of B cells (32;33). Some patients also have reduced numbers of NK cells and increased numbers of T lymphocytes (32). Dominant negative mutations in IKZF1 are linked to acute lymphoblastic leukemia (ALL) in infants and adults (41-43). Patients with ALL exhibit uncontrolled B-lymphoid progenitor expansion in the bone marrow.

Ikzf1-deficient (Ikzf1-/-) mice typically (95%) exhibited postnatal lethality by four weeks of age due to bacterial infections (28). The Ikzf1-/-mice exhibited reduced body sizes compared to wild-type mice (28). Ikzf1-/- mice exhibited reduced circulating adrenocorticotrophic hormone levels, adrenal glucocorticoid insufficiency, and contraction of the pituitary corticomelanotroph population due to loss of IKAROS-associated proopiomelanocortin gene expression (44). Homozygous mice expressing an ENU-induced mutant Ikzf1 allele (Ikzf1plastc/plastc; H191R) exhibited embryonic lethality between embryonic days 15.5 and 17.5 due to fetal anemia (29). The Ikzf1plastc/plastc embryos showed thymus and liver hypoplasia, a failure in T and B cell differentiation, increased numbers of granulocyte/macrophage progenitor cells, reduced numbers of erythroid progenitor cells, aberrant erythroblast differentiation and growth (29). Homozygous mice expressing a mutant Ikzf1 allele that is missing zinc finger 1 (Ikzf1deltaF1/deltaF1) exhibited reduced numbers of immature B cells as well as pre-B, B1a, and B1b cell numbers, thymus hypoplasia, and reduced numbers of DN1 thymic pro-T cells (30).

Putative Mechanism

Ikzf1-/- mice also exhibited reduced numbers of B1a, B1b cells, NK cells, and double-positive T cells, deficient B cell differentiation, reduced spleen germinal center number, aberrant B cell activation and proliferation after IL-7 stimulation, and reduced IgG3 levels (12;28;31).

The phenotype of the star_lord mice indicates abberant IKZF1star_lord-associated function in lymphocyte differentiation and function.

Primers PCR Primer
Star_lord_pcr_F: AGCGGCCTTATCTACCTAACC
Star_lord_pcr_R: AACATTGTCCGCTGTGGGTC

Sequencing Primer
Star_lord_seq_F: GGCCTTATCTACCTAACCAACCAC
Star_lord_seq_R: AGGAGGCATAACCAGCTATCTTTGTG
Genotyping

PCR program

1) 94°C 2:00
2) 94°C 0:30
3) 55°C 0:30
4) 72°C 1:00
5) repeat steps (2-4) 40x
6) 72°C 10:00
7) 4°C hold


The following sequence of 416 nucleotides is amplified (chromosome 11, + strand):


1   agcggcctta tctacctaac caaccacatc aacccgcatg cacgcaatgg gctggctctc
61  aaggaggagc agcgcgccta cgaggtgctg agggcggcct cagagaactc gcaggatgcc
121 ttccgtgtgg tcagcacgag tggcgagcag ctgaaggtgt acaagtgcga acactgccgc
181 gtgctcttcc tggatcacgt catgtatacc attcacatgg gctgccatgg ctttcgggat
241 ccctttgagt gtaacatgtg tggttatcac agccaggaca ggtacgagtt ctcatcccat
301 atcacgcggg gggagcatcg ttaccacctg agctaaaccc agccaggccc cactgaagca
361 caaagatagc tggttatgcc tccttcccgg cagctggacc cacagcggac aatgtt


Primer binding sites are underlined and the sequencing primers are highlighted; the mutated nucleotide is shown in red.

References
Science Writers Anne Murray
Illustrators Diantha La Vine
AuthorsSamantha Teixeira, Xue Zhong, Jin Huk Choi, and Bruce Beutler