Display Settings:

Format

Send to:

Choose Destination
See comment in PubMed Commons below
Haematologica. 2009 Sep;94(9):1203-10. doi: 10.3324/haematol.2008.002881. Epub 2009 Jul 16.

First mutation in the red blood cell-specific promoter of hexokinase combined with a novel missense mutation causes hexokinase deficiency and mild chronic hemolysis.

Author information

  • 1Department of Clinical Chemistry and Hematology, Laboratory for Red Blood Cell Research, University Medical Center Utrecht, The Netherlands. k.devooght@umcutrecht.nl

Abstract

BACKGROUND:

Hexokinase is one of the key enzymes of glycolysis and catalyzes the phosphorylation of glucose to glucose-6-phosphate. Red blood cell-specific hexokinase is transcribed from HK1 by use of an erythroid-specific promoter. The aim of this study was to investigate the molecular basis for hexokinase deficiency in a patient with chronic hemolysis.

DESIGN AND METHODS:

Functional studies were performed using transient transfection of HK promoter constructs in human K562 erythroleukemia cells. The DNA-protein interaction at the promoter of hexokinase was studied using electrophoretic mobility shift assays with nuclear extracts from K562 cells. DNA analysis and reverse transcriptase polymerase chain reaction were performed according to standardized procedures.

RESULTS:

On the paternal allele we identified two novel mutations in cis in the erythroid-specific promoter of HKI: -373A>C and -193A>G. Transfection of promoter reporter constructs showed that the -193A>G mutation reduced promoter activity to 8%. Hence, -193A>G is the first mutation reported to affect red blood cell-specific hexokinase specific transcription. By electrophoretic mobility shift assays we showed that in vitro binding of c-jun to an AP-1 binding site was disrupted by this mutation. Subsequent chromatin-immunoprecipitation assays demonstrated that c-jun binds this region of the promoter in vivo. On the maternal allele we identified a novel missense mutation in exon 3: c.278G>A, encoding an arginine to glutamine substitution at residue 93, affecting both hexokinase-1 and red cell specific-hexokinase. In addition, this missense mutation was shown to compromise normal pre-mRNA processing.

CONCLUSIONS:

We postulate that reduced erythroid transcription of HK1 together with aberrant splicing of both hexokinase-1 and red cell specific-hexokinase results in hexokinase deficiency and mild chronic hemolysis.

PMID:
19608687
[PubMed - indexed for MEDLINE]
PMCID:
PMC2738711
Free PMC Article

Images from this publication.See all images (5)Free text

Figure 1.
Figure 2.
Figure 3.
Figure 4.
Figure 5.
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Icon for HighWire Icon for PubMed Central
    Loading ...
    Write to the Help Desk