Transcription and proper splicing of a mammalian gene in yeast.

The house mouse strain C57BL/6 harbours 64 copies of the multicopy gene Sp100-rs. Three of these are contained in the yeast artificial chromosome (YAC) clone yMm75. Four Sp100-rs transcripts of 3.0, 2.6, 1.6 and 1.3kb were detected by Northern hybridization in the yMm75-harbouring line of Saccharomyces cerevisiae. Additional and less abundant transcripts were detected by RT-PCR. With one exception, the YAC-derived Sp100-rs transcripts were a subset of those found in the C57BL/6 mouse. This indicates transcription and proper splicing of murine pre-mRNAs in yeast. Analysis of the splice sites shows that the yeast splicing machinery accepts splice sites that deviate from the standard yeast consensus sequences. It may be feasible, therefore, at least in a fair proportion of cases, to exploit the mammalian mRNAs present in transgenic yeast for gene recognition of YAC-inserts.