Transcription interferes with elements important for chromosome maintenance in Saccharomyces cerevisiae.

Abstract

Transcription directed into a Saccharomyces cerevisiae autonomously replicating sequence (ARS) causes high-frequency loss of minichromosomes. Conditionally stable artificial yeast chromosomes were constructed that contain an inducible GAL promoter upstream of ARS). Under growth conditions in which the promoter was inactive, these chromosomes were mitotically stable; however, when the GAL promoter was induced, the chromosomes became extremely unstable as a result of transcriptional impairment of ARS function. This interference by the GAL promoter occurred only in cis but can occur from either side of ARSI. Transcriptional interference ofARS function can be monitored readily by using a visual colony-color assay (P. Hieter, C. Mann, M. Snyder, and R. W. Davis, Cell 40:381-392, 1985), which was further developed as a sensitive in vivo assay for sequences which rescue ARS from transcription. DNA fragments from the 3' ends of genes, inserted downstream of the GAL promoter, protected ARS function from transcriptional interference. This assay is expected to be independent of both RNA transcript stability and processing. Philippsen et al. have shown that transcription into a yeast centromere inhibits CEN function in vivo

Perturbation of the Activity of Replication Origin by Meiosis-specific Transcription

“…3). A similar result has been reported by an artificial system, where the gal promoter fused to ARS1 does abolish origin activity when transcription is induced by galactose, although no molecular mechanism is indicated (27). Here, we demonstrated clearly that replication origin activity was negatively regulated through transcription, which interfered the binding of ORC complex to the replication origin either directly by running of RNA polymerase or indirectly by transcription-associated events like changes in DNA topology or chromatin structure.…”

“…It was reported previously that the origin function of an ARS1 was inactivated by strong transcription that run through it (27). However, it…”

“…ARS605 is located within the ORF of MSH4 (a MutS homolog) and transcribed in early meiosis (25,26). We assumed that the loss of ARS605 activity was because of the MSH4 transcription because it is known that transcription from a strong galactose inducible promoter interferes with origin functions on plasmid (27).…”

Execution of the meiotic noncoding RNA expression program and the onset of gametogenesis in yeast require the conserved exosome subunit Rrp6

“…Other MUTs could regulate ARS elements during sporulation via transcription interference (38). For example, the mitotically active ARS605 was shown to be inhibited during meiotic prophase by the expression of the early meiotic gene MSH4, which precludes Orc1 binding to its target motif (39).…”

Analysis of the Structure of a Natural Alternating d(TA)n Sequence in Yeast Chromatin

“…Other ARS consensus sequences without autonomous replication capability have also been found in the 3 end regions of other genes, and their functional significance, if any, is not known (J. E. Pérez-Ortín, unpublished observations). Amati and Gasser (1988) have found in yeast a relationship between ARS elements and SARs and it has been proposed that the scaffold binding protects these elements from incoming transcription (Snyder et al, 1988). We have not analysed either the SAR, or the topo II binding properties of this sequence.…”