Research Home Page

Research projects
» tRNA primer
» Temperature resistant transposition
 

The mhis3AI marker gene

This Ty1 marker gene is not expressed from the plasmid but is expressed if transposed into the host genome (Curcio and Garfinkel). This marker gene, mhis3AI (detailed in the figure below), was constructed by cloning the HIS3 gene into Ty1 in the reverse orientation of Ty1 transcription. Inserted into the HIS3 coding region is an artificial intron (AI) with splice donor and acceptor sites in the same transcriptional orientation as Ty1. The mhis3AI gene carries a HIS3 promoter but produces an inactive protein due to the inserted intron. Induction of Ty1 transcription in galactose-containing medium produces a Ty1 mRNA containing an intron, which is subsequently spliced out. This RNA now contains, at the 3’ end, anti-sense HIS3 RNA. If this RNA is successfully reverse transcribed and integrated into the genome, a functional HIS3 gene is formed.