ABO transcript levels in peripheral blood and erythropoietic culture show different allele-related patterns independent of the CBF/NF-Y enhancer motif and multiple novel allele-specific variations in the 5'- and 3'-noncoding regions

Transfusion. 2008 Mar;48(3):493-504. doi: 10.1111/j.1537-2995.2007.01554.x. Epub 2007 Dec 7.


Background: Mechanisms regulating the ABO gene are unclear, especially in the hematopoietic compartment. The number of 43-bp repeats in the CBF/NF-Y-binding enhancer region is considered to have a major influence on transcription.

Study design and methods: Transcript levels in peripheral blood and in erythropoietic culture of CD34+ cells from marrow donors were measured with TaqMan assays. The 5'-regulatory region and 3'-downstream sequences were investigated to determine if allelic variations occur.

Results: Surprisingly, transcripts from A(1) and A(2) alleles could not be detected in peripheral blood, although transcripts from B/O(1)/O(1v)/O(2) alleles were readily observed. Sequencing of approximately 4 kb upstream and 1.8 kb downstream of the coding region showed multiple novel allele-specific and allele-related motifs. No correlation between these sequence variations and transcript levels was found, however. Contradictory to the results with peripheral blood, in erythropoietic culture of CD34+ cells from healthy marrow donors transcripts from A(1) and A(2) alleles were found at higher levels than transcripts from B/O(1)/O(1v) alleles.

Conclusion: These data do not support previous suggestions that nonsense-mutated O(1)/O(1v) transcripts are eliminated first. Furthermore, our results contradict the notion that the number of repeats in the upstream CBF/NF-Y-binding enhancer region, which contains four 43-bp repeats in A(2)/B/O(1)/O(1v) but only one 43-bp unit in A(1)/O(2) alleles, determines the transcription rate. The reason for the remarkable discrepancy between blood and marrow remains to be elucidated.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • ABO Blood-Group System / genetics*
  • Alleles*
  • Antigens, CD34 / blood
  • Base Sequence
  • Binding Sites / genetics
  • Bone Marrow Cells / metabolism
  • CCAAT-Binding Factor / genetics*
  • Cells, Cultured
  • Enhancer Elements, Genetic / genetics*
  • Genetic Variation
  • Humans
  • Molecular Sequence Data
  • Polymerase Chain Reaction
  • Polymorphism, Genetic
  • Transcription, Genetic


  • ABO Blood-Group System
  • Antigens, CD34
  • CCAAT-Binding Factor