Structure of the human zinc finger protein HIVEP3: Molecular cloning, expression, exon-intron structure, and comparison with paralogous genes HIVEP1 and HIVEP2

Here we report the cloning and characterization of HITEP3; the newest membe r in the human immunodeficiency virus type 1 enhancer-binding protein famil y that encodes large zinc finger proteins and regulates transcription via t he KB enhancer motif. The largest open reading frame of HIVEP3 contains 240 6 aa. and is similar to 80% identical to the mouse counterpart. The HIVEP3 gene is located in the chromosomal region 1p34 and is at least 300 kb with 10 exons. RNA studies show that multiple HP3 transcripts are differentially expressed and regulated. Additionally, transcription termination occurs in the ultimate exon, exon 10, or in exon 6. Therefore, HIVEP3 may produce pr otein isoforms that contain or exclude the carboxyl DNA binding domain and the leucine zipper by alternative RNA splicing and differential polyadenyla tion. Sequence homologous to HIVEP3 exon 6 is not found in mouse nor are th e paralogous genes HIVEP1 and HIVEP2. Zoo-blot analysis suggests that seque nces homologous to the human exon 6 are present only in primates and cow. T herefore, a foreign DNA harboring a termination exon likely was inserted in to the HIVEP3 locus relatively recently in evolution, resulting in the acqu isition of novel gene regulatory mechanisms as well as the generation of st ructural and functional diversity. (C) 2001 Academic Press.