HUMAN TRANSFORMER-2-BETA GENE (SFRS10) - COMPLETE NUCLEOTIDE-SEQUENCE, CHROMOSOMAL LOCALIZATION, AND GENERATION OF A TISSUE-SPECIFIC ISOFORM

Htra2-beta is a human homologue of Drosophila transformer-2 and a memb er of the SR-like protein family. Here we report the isolation and cha racterization of the complete htra2-beta gene (HGMW-approved symbol SF RS10). The gene spans 21,232 bp and is composed of 10 exons and 9 intr ons. Radiation hybrid mapping localized the gene to chromosome 3q. The region upstream of the transcription initiation codon contains an Alu element and several potential transcription factor binding sites. RT- PCR and comparison with EST clones revealed five different RNA isoform s generated by alternative splicing. These isoforms encode three diver ging open reading frames, and two of these, htra2-beta3 and htra2-beta 4, lack the first SR domain. Htra2-beta3 is developmentally regulated and expressed predominantly in brain, liver testis, and weakly in kidn ey. Furthermore, the domain structure of htra2-beta3 resembles a varia nt found in the Drosophila male germline, indicating a remarkable cons ervation of alternative transformer-a variants. Finally, we show that htra2-beta3 is expressed in the nucleus and interacts with a subset of SR proteins in a yeast two-hybrid system and in vivo. (C) 1998 Academ ic Press.