JAML mRNA is up-regulated during induced differentiation of myeloid leukemia cells and is expressed in normal hematopoietic tissues. (A) Up-regulation of JAML mRNA during induced differentiation of myeloid leukemia cells. Autoradiograms of JAML mRNA expression before and after treatment of HL-60 and PLB-985 cells with different inducers of differentiation. Northern blots were performed using 5 μg total RNA. Hybridization with a GAPDH probe controlled for RNA quantities in each lane. (B) Autoradiograms of JAML mRNA expression in immune tissues (i) and peripheral blood cells (ii). Northern blots were either obtained from Clontech (i) or were performed using 5 μg total RNA from granulocytes, monocytes, and lymphocytes (ii). In panels A and B, GAPDH was used as a probe for assessment of RNA quantities in each lane.
U937/MT, U937/MT-JAML-HA, and U937/MT-JAMLK54D-HA cells stably transfected with the pMT, the pMT-JAML-HA, or pMT-JAMLK54D-HA respectively were untreated (-Zn) or treated (+Zn) with ZnSO4 for 18 hours prior to fluorescent labeling and subjected to a cell adhesion assay using human bone marrow endothelial cells either untreated (HBMECs) or treated (HBMECs + TNFα) as a target layer. Results are expressed in each condition as the amount of released fluorescence from adherent cells, normalized to unity for the corresponding -Zn/-TNFα condition. The adhesion level of U937/MT-JAML-HA cells onto untreated or TNFα-pretreated HBMECs, in the absence of Zn treatment (-Zn), was measured as 2.3% and 15.5% respectively, of the total number of incubated cells. Values shown are ± SD.
