Identification, characterization and mapping of the human ZIS (zinc-finger, splicing) gene

From a human fetal brain cDNA library, we isolated two transcripts (ZIS-1 a nd ZIS-2) corresponding to the human ZIS gene, an ortholog of the rat Zis ( zinc finger, splicing). A comparison of base sequences of the cDNA and its corresponding genomic DNA (a Pi-derived artificial chromosome clone) reveal ed that both transcripts have an ORF of 1011 bp and encodes 337 amino acids , but ZIS-1 has 10 exons and ZIS-2 contains 11 exons. Although both transcr ipts share the first nine exons, exon 10 of ZIS-2 is lacking in ZIS-1, and instead, exon 11 (10th exon) of ZIS-1 is larger in size, leading to the lon ger 3'-UTR. Thus, the two transcripts result from differential splicing. A Northern blot analysis on various adult and fetal tissues revealed that 5.2 - and 3.2-kb transcripts were ubiquitously expressed, and 3.9- and 1.9-kb t ranscripts were highly expressed in the fetal brain and kidney, respectivel y. There were several other transcripts that may be alternatively processed forms of the human ZIS. Considering the ZIS gene size, the 3.2-kb transcri pts most likely corresponds to ZIS-1 and may act as a major transcript of Z IS. The human ZIS has a high homology to the rat Zis for the coding DNA seq uence with 91% identity and for the amino acid sequence with 87% identity. ZIS and Zis contain the same numbers of exons and introns. Both genes have unusually long 3'-UTR, and their encoding proteins contain similar componen ts, i.e. a zinc finger domain, a nuclear localization signal, an Asp-Glu re gion, and a Ser-Arg-rich region. Furthermore, the expression patterns of th e two genes in tissues are similar each other. Thus, the human ZIS may act as a transcriptional factor to regulate transcription and/or splicing, as d oes the rat Zis. (C) 1998 Elsevier Science B.V. All rights reserved.