The Znfl31/ZNFl31 protein belongs to the superfamily of POK proteins containing a BTB/POZ domain in its N-terminal part and 5 typical C2H2 zinc fingers and an additional C2H2 zinc finger structure in its C-terminal region. In mouse and human two alternatively spliced transcripts are expressed from the Znfl31/ZNFl31 gene, resulting from intraexonic splicing. While the longer transcript encodes for three double zinc finger structures the shorter transcript lacks the region coding for the first zinc finger. Although the murine Znfl31 gene is ubiquitously expressed, expression analysis applying whole mount in situ hybridization showed a predominant expression in the developing central nervous system with strongest signals in the forebrain, midbrain, and hindbrain areas and in the neural tube. Further dominant expression was seen in embryonic limb buds. In human adult tissues a predominant expression of ZNFl31 was seen in different brain areas, i,e., the occipital and temporal lobe, the nucleus caudatus, hippocampus, and the cerebellum as well as in testis and thymus. Therefore. it is possible that Znfl31/ZVFl31 plays a role during development and organogenesis as well as in the function of the adult central nervous system. (C) 2002 Elsevier Science (USA). All rights reserved.