The effect of human IgC lambda fragments on gene expression in transfected mouse fibroblasts.

We have determined the effect of fragments of the human IgC lambda region on the expression of a linked marker gene on transfection into heterologous LATK cells. No Ig fragment stimulated high expression of the bacterial chloramphenicol acetyl transferase gene under conditions where high activation by the Moloney MSV enhancer was observed. This suggests that there is not an element in this DNA fragment which behaves as a strong enhancer in fibroblast cells. Sequences localised within a 0.9 kb fragment 3' to the Ke-Oz- constant region gene showed low (four fold) stimulation of CAT activity. These results are discussed in relation to measuring gene activity by protein expression assays.