Comparison of murine Supt4h and a nearly identical expressed, processed gene: Evidence of sequence conservation through gene conversion extending into the untranslated regions

We show herein the transcription of a processed gene that originated from a spliced transcript. Recently, we isolated the human and murine homologues of the yeast chromatin protein, SPT4. The Supt4h gene is spliced normally from five exons encoded by chromosome 11. Here we show that a related sequence on chromosome 10 encodes Supt4h2, a processed intronless gene (with a polyA tail and a tandemly-duplicated 13 bp insertion site in the genome) with a different 5' control region. Both the spliced gene, Supt4h, and the processed gene, Supt4h2, are expressed in each of four tissues we examined. Supt4h2 encodes a 117 amino acid protein nearly identical to the Supt4h gene product with only one amino acid difference, indicating extreme conservation of this expressed processed gene with the spliced gene over evolutionary time. This illustrates another potential complexity of the mammalian genome, i.e. the use of a processed gene under the control of a different promoter region than the spliced gene.