For example, a transfected beta-globin gene is expressed in an inducible manner in mouse erythroleukemia (MEL) cells while a transfected alpha-globin gene is constitutively expressed at a high level in induced and uninduced MEL cells.
We describe the negative regulatory activity of a 1.7 kilobase (kb) region (R) in the human beta-globin locus located between 4.0 and 2.3 kb upstream of the delta-globin gene capsite, using a transient assay with the chloramphenicol acetyltransferase (CAT) reporter gene in mouse erythroleukemia (MEL) cells.
We suggest that operationally positive regulatory factors may exist in erythroleukemia cells, modifying the relative alpha 1- and alpha 2-globin gene expression by events following induction and by the adult MEL environment.
To determine whether sequences contained within the small intervening sequence (IVS 1) or large intervening sequence (IVS 2) are involved in the regulated expression of the human beta-globin gene, chimeric genes containing portions of the human beta- and delta-globin genes were stably transfected into mouse erythroleukemia (MEL) cells.
The levels of human alpha-globin mRNA in these hybrid cells were found to depend on factors present in the MEL recipient cell as well as on the differentiated state of the human donor cell, suggesting that this system may be suitable for characterisation of mechanisms governing haematopoietic differentiation in man.