T. Yoshimatsu et F. Nagawa, EFFECT OF ARTIFICIALLY INSERTED INTRON ON GENE-EXPRESSION IN SACCHAROMYCES-CEREVISIAE, DNA and cell biology, 13(1), 1994, pp. 51-58
The intron of the yeast RP51A gene was cloned with precision using the
polymerase chain reaction (PCR) amplification method, and then insert
ed into several different positions of the yeast URA3 gene as well as
the PGK-lacZ fusion gene without introduction of additional exon seque
nces. Analysis of transcripts of these genes showed that an intron ins
erted near the transcription start site of the gene was spliced out ef
ficiently, whereas the same intron sequences inserted 200 hp or furthe
r downstream of the start site were not, resulting in a reduced level
of mRNA. These results explain why intron-containing genes in yeast us
ually have an intron near the 5' end.