Expression of the BCL6 gene in the pre- and postnatal mouse

Human BCL6, also called LAZ3, is a protein involved in gene regulation and abnormal expression of BCL6 and has been implicated in the tumorigenesis of non-Hodgkin lymphoma. We have analyzed the expression of murin bcl6 in pre- and postnatal mouse using in situ hybridization histochemistry and Northern blotting. The developing olfactory epithelium in the nasal cavity was the only tissue displaying a positive bcl6 mRNA signal in the day 14 embryo. At gestational day 17, expression was primarily seen in skeletal muscle, olfactory epithelium, and thymus, and also in the epithelium lining the upper airways and esophagus. In selected tissues from postnatal mouse, bcl6 expression was detected in brain, renal cortex, spleen, and thymus. The expression in brain was restricted to the pyramidal cell layer of the cerebral cortex and the hippocampus regions CA1 and CA2, and the dentate gyrus. Our results show that bcl6 expression is not confined only to organs of the lymphatic system, such as spleen and thymus. Thus, bcl6 may be active as a regulator of gene transcription in many different cell types, including epithelial and nerve cells.