The first exon of the human sc gene contains an androgen responsive unit and an interferon regulatory factor element

Secretory component (SC) plays a key role in the transport of IgA and IgM t o the lumina of many glands. The gene is constitutively expressed, but can be modulated by hormonal and immunological stimuli. Recently, the promoter and the first exon of the human sc gene have been cloned. The first exon co ntains a putative androgen/glucocorticoid response element (ARE/GRE) and an Interferon Regulatory Factor Element (IRF-E). Here we show that the ARE/GR E can bind the DNA-binding domain (DBD) of both the androgen (AR) and gluco corticoid receptor (GR) with a preference for the AR-DBD. In transient tran sfection experiments, this element confers higher responsiveness to androge ns than to glucocorticoids. The IRF-E can function as an IRF-2, but surpris ingly not as an IRF-1 responsive element. We postulate that these two regul atory elements play a key role in the complex regulation of the sc gene in vivo. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.