ABSTRACT
The objective of this study was to observe the expression of hoxc4 and hoxc6 genes in the process of differentiation of hematopoietic stem cell (HSC) to colony forming unit-T Lymphocyte (CFU-TL) in vitro. and to explore the possible mechanism of HCMV-induced maldevelopment of human cord blood CFU-TL on genetic level through effecting the differentiation progress by human cytomegalovirus (HCMV) with and/or all-trans retinoic acid (ATRA), Normal CFU-TL culture was used as blank control. After detection with MTT, mRNA expression levels in the human cord blood CFU-TL hoxc4 and hoxc6 genes following HCMV infection and ATRA treatment were detected by fluorogenic quantitative reserve transcription polymerize chain reaction (FQ-RT-PCR) method. HCMV of 10(6) plaque formation unit (PFU)/ml was diluted to 0.1 ml 10(5) PFU/ml and added into the infected group. The results showed that the expression of hoxc4 and hoxc6 genes in the differentiation process increased slightly on day 3, and were up to the most on day 7 (p < 0.05), while became lower on day 12 respectively in normal group, HCMV group and ATRA group. Compared with the expression of hoxc6, the expression of hoxc4 was obviously higher in each group (p < 0.05). Compared with the expression of hoxc4 and hoxc6 genes in normal group, the expressions of hoxc4 and hoxc6 in ATRA group were up-regulated remarkably (p < 0.05), while the expressions of hoxc4 and hoxc6 in group HCMV were down-regulated (p < 0.05). It is concluded that the regular expression of hoxc4 and hoxc6 genes mRNA appeared in each group. A positive co-relationship exits between hoxc4/hoxc6 genes and lymphocytic progenitor hematopoiesis. Compared with the expression of hoxc6 gene, the expression of hoxc4 gene is obviously higher in each group. HCMV can down-regulate the expression of hoxc4 and hoxc6 genes and lead to suppression effect on cell morphology, which confirms that the normal hematopoietic lineage determination and maturation rely on the stable and consistent expression of homeobox gene. At the same condition, ATRA (6 x 10(-8) mol/L at 60 nmol/ml) can up-regulate hoxc4 and hoxc6 genes expression. ATRA can up-regulate the expression of hoxc4 and hoxc6 genes.