Transcriptional repressor which suppresses activation protein 1 (AP-1)- and serum response element (SRE)-mediated transcriptional activity. Widely expressed in various adult tissues and embryonic developmental stages (isoform 3). Shows a relatively higher expression level in the fetal brain and a lower level in adult. The expression level in liver is highest at 16 weeks of development and declines from 16 to 24 weeks and is lower in adult. Expressed strongly in fetal heart on 18 and 24 weeks, but relatively weakly on the other development stage of embryo, and then reaches a higher level in adult (isoform 3). Belongs to the krueppel C2H2-type zinc-finger protein family. Truncated N-terminus. Extended N-terminus.