Structure, chromosome mapping and regulation of the mouse zinc-finger gene Krox-24; evidence for a common regulatory pathway for immediate-early serum-response genes.

The structure of Krox-24, a mouse zinc-finger-encoding gene that is transiently activated during G0/G1 transition, has been established. Krox-24 is located on mouse chromosome 18, bands C-D. The gene product, as anticipated for a putative DNA-binding protein, is localized within the cell nucleus. The Krox-24 5'-flanking region contains a series of serum response elements (SREs) similar to the SRE observed upstream of the c-fos proto-oncogene. These elements can substitute for the c-fos SRE, their effect is cumulative and they bind the same cellular factor, the serum response factor (SRF), as the c-fos SRE. This suggests that the SRE and its cognate protein are likely to be involved in the regulation of Krox-24 and presumably of other immediate-early serum response genes. SRE and SRF therefore constitute key components in the regulatory pathway leading from mitogenic stimulation to cellular proliferation.