The 5' region of the human hSUV3 gene encoding mitochondrial DNA and RNA helicase: promoter characterization and alternative pre-mRNA splicing.

The human nuclear hSUV3 gene encodes ATP-dependent RNA and DNA helicase, which predominantly localizes in the mitochondria. In yeast, the Suv3 helicase is a component of mitochondrial degradosome, a two-subunit complex, which degrades aberrant mtRNAs. In contrast to the well-documented physiological role of the yeast SUV3, the function of its human orthologue remains unknown. In this report, we have analyzed the hSUV3 5' genomic region. Our data suggest that hSUV3 is a housekeeping gene. Deletion analysis and in vitro mutagenesis revealed the presence of an enhancer region and regulatory elements in basal promoter including: (i) direct 10-bp-long repeats, which share significant sequence similarity with the consensus for the NF-kappaB/Rel family transcription factors, (ii) Sp1 general transcription factor binding site, and (iii) NRF-1 transcription factor binding sites, the latter typical for nuclear-encoded mitochondrial genes. Furthermore, we show that the 5' region of the hSUV3 pre-mRNA can be alternatively spliced.