In:
Blood, American Society of Hematology, Vol. 128, No. 22 ( 2016-12-02), p. 1246-1246
Abstract:
The mommeD45 mutation generates an amino acid transversion (H350R) within a conserved linker peptide between zinc fingers two and three of Klf1 (linker 2). Klf1H350R/H350R mice have mild compensated microcytic anaemia 1. Mice Carrying the H350R mutation were interbred with Klf1+/- mice. Klf1H350R/-mice have severe perinatal haemolytic anaemia, jaundice and marked splenomegaly. Haematological evaluation of these mice shows similar phenotypes to human patients who are compound heterozygotes for null and linker 2 mutations in KLF12. Analysis of Klf1H350R/- fetal liver by flow cytometry showed an increase in circulating immature CD71+ Ter119+ erythroblasts. In the bone marrow, a marked reduction in mature (Cd71- Ter119+) red blood cells was observed. Flow cytometric analysis of the spleen from Klf1H350R/- animals revealed an expansion of erythroid cells consistent with extramedullary erythropoiesis. ChIP-seq for Klf1 in 14.5DPC fetal liver from Klf1H350R/H350R mice revealed no loss in specificity when compared to wildtype Klf1, but a global reduction in affinity. Affinity measurements of recombinant zinc finger domains in vitro will be presented. By RNA-seq, we observed significantly lower expression of Klf1 target genes in mice homozygous for the H350R mutation compared to mice carrying a wildtype allele. And this correlates with reduced DNA binding observed in ChIP-seq and in vitro assays. Previous studies of the linkers in C2H2 zinc finger transcription factors have revealed their necessity as structural and regulatory components for the C2H2 class of transcription factors. Our results show the second linker of Klf1 plays an indirect role in DNA-binding and does not act just as a spacer for the zinc fingers. References: 1. Sorolla A, Tallack MR, Oey H, et al. Identification of novel hypomorphic and null mutations in Klf1 derived from a genetic screen for modifiers of alpha-globin transgene variegation. Genomics. 2015;105(2):116-122. 2. Viprakasit V, Ekwattanakit S, Riolueang S, et al. Mutations in Kruppel-like factor 1 cause transfusion-dependent hemolytic anemia and persistence of embryonic globin gene expression. Blood. 2014;123(10):1586-1595. Disclosures Perkins: Novartis Oncology: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Honoraria.
Type of Medium:
Online Resource
ISSN:
0006-4971
,
1528-0020
DOI:
10.1182/blood.V128.22.1246.1246
Language:
English
Publisher:
American Society of Hematology
Publication Date:
2016
detail.hit.zdb_id:
1468538-3
detail.hit.zdb_id:
80069-7
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