Northern blot analysis shows that human Sn mRNA is expressed in macrophage-like cell lines and in the spleen.

A total of 10 μg mRNA from the indicated sources was loaded in each lane. The blot was probed with a 1.2-kb EcoRI fragment of pTH1 (top panel) or with a human actin cDNA to control for loading (bottom panel). A single transcript of 7.5 kb is present in THP-1 cells, PMA-treated U937 cells, and in human spleen. Cell lines are as follows: THP-1, monocytic; U937, promonocytic; Daudi, B-cell; K562, myeloerythroid.