Analysis on promoter CpG methylation and expression of HOXB4 gene in cord blood CD34(+) cells and peripheral blood mononuclear cells / 中国实验血液学杂志

ABSTRACT

This study was aimed to examine the expression and promoter CpG island methylation of homeobox B4 (HOXB4) gene in CD34(+) cells from cord blood and peripheral blood mononuclear cells (PBMNCs) from health adult, and to investigate the expression level of HOXB4 in these two cells and its relationship with the promoter methylation. Semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) was used to examine the expression of HOXB4 in CD34(+) cells and PBMNCs, and bisulfite sequencing technique was used to detect the methylation status of the promoter CpG sites of HOXB4 gene in CD34(+) cells and PBMNCs. The results indicated that highly expressed HOXB4 and unmethylation of HOXB4 promoter CpG island occurred in CD34(+) cells. However, loss of HOXB4 expression and the methylated CpG island of HOXB4 were observed in PBMNCs, and the methylated C residue was positioned at -129 bp in the upstream of ATG. It is concluded that the methylation status of HOXB4 gene promoter may be one negative regulatory mechanism for HOXB4 gene expression. The unmethylation of CpG island in the promoter region of HOXB4 gene may be correlated with the high expression of HOXB4 gene in CD34(+) cells, while the promoter methylation of HOXB4 gene may be associated with HOXB4 gene silencing in PBMNCs. The preliminary identification of HOXB4 promoter methylation site would provide a basis for further study and a novel approach to expand hematopoietic progenitor cells.