Web supplement |
Welcome to the web supplement to the paper:
"Recruitment of terminal protein to the ends of Streptomyces linear plasmids
and chromosomes by a novel telomere binding protein essential for linear DNA
replication". Kai Bao and Stanley N. Cohen.
published in
Genes & Development, Vol. 17, Issue 6, pp. 774-785, March 15, 2003
Abstract
Bidirectional replication of Streptomyces linear plasmids and chromosomes from
a central origin produces unpaired 3' leading strand overhangs at the
telomeres of replication intermediates. Filling in of these overhangs leaves
a terminal protein attached covalently to the 5' DNA ends of mature
replicons. We report here the essential role of a novel 80 kDa DNA binding
protein (telomere associated protein; Tap) in this process. Biochemical
studies, yeast two hybrid analysis, and immunoprecipitation/immunodepletion
experiments indicate that Tap binds tightly to specific sequence in 3'
overhangs and also interacts with Tpg, bringing Tpg to telomere termini.
Using DNA microarrays to analyze the chromosomes of tap mutant bacteria, we
demonstrate that Tap ablation leads to telomere deletion, chromosome
circularization, and amplification of subtelomeric DNA. Microarray-based
chromosome mapping at single ORF resolution revealed common endpoints for
independent deletions, identified amplified chromosomal ORFs adjacent to these
endpoints, and quantified copy number of these ORFs. Sequence analysis
confirmed chromosome circularization and revealed the insertion of
adventitious DNA between joined chromosome ends. Our results show that Tap is
required for linear DNA replication in Streptomyces and suggest that it
functions to recruit and position Tpg at the telomeres of replication
intermediates. They also identify hotspots for the telomeric deletions and
subtelomeric DNA amplifications that accompany chromosome circularization.
Supplemental Data
In this webpage you can find the primary microarray data and a large picture of Figure 6.