Comparative Study Of Differentially Expressed Genes In Mouse Bone Marrow And Fetal Liver

The development of hematopoiesis underwent a serials of migrations from yolk sac to liver and spleen, and finally located in bone marrow until the end of life. A number of investigations have demonstrated that the hematopoietic microenvironment plays very important roles in this process. But the exact mechanisms remain unknown. In order to systematically analyze and understand the roles of hematopoietic inductive microenvironment (HIM) in the regulation and control of hematopoiesis, a microarray containing 588 complementary DNAs (cDNAs) was used to compare the gene expressions between murine fetal liver ( FL ) and bone marrow ( BM ) cells. The results obtained from microarray hybridization were analyzed and reconfirmed by using bioinformatics and RT-PCR as well as Northern Blot. Our experimental results showed that 65 and 131 genes were relatively high expressed in bone marrow and fetal liver respectively among 588 known genes in the array-membrane. According to the survey in the PubMed, 39 in bone-marrow-expressed genes and 71 genes in fetal-liver-expressed genes are closely related to the hematopoiesis. Further reconfirmation by RT-PCR or Northern Blot has demonstrated that CD 18, CD44 and PSGL-1 genes chosen for analysis were highly expressed in adult bone marrow, but unexpressed or lower expressed in fetal Hver, resulting in highly similar to the array results. Moreover, the experimental results also showed that the expressions of CD 18 and CD44 in fetal liver were down regulated with the increasing of gestational age. Our results have demonstrated that the genes expression in bone marrow and fetal liver are obviously different, some of the genes are down-regulated at the different stages of ontogeny. The different gene expression levels between bone marrow and fetal liver, especially those genes closely related to the hematopoiesis, may be the molecular basis for the explanation of why hematopoietic stem/ progenitor cells (HSPCs) derived from different tissues have different characterizations and functions as well as the beginning and stop of fetal liver hematopoiesis, and why HSPCs derived from fetal liver is tremendously difficult to be grafted in bone marrow.