Novel features of ARS selection in budding yeast Lachancea kluyveri.
BACKGROUND
The characterization of DNA replication origins in yeast has shed much light on the mechanisms of initiation of DNA replication. However, very little is known about the evolution of origins or the evolution of mechanisms through which origins are recognized by the initiation machinery. This lack of understanding is largely due to the vast evolutionary distances between model organisms in which origins have been examined.


RESULTS
In this study we have isolated and characterized autonomously replicating sequences (ARSs) in Lachancea kluyveri - a pre-whole genome duplication (WGD) budding yeast. Through a combination of experimental work and rigorous computational analysis, we show that L. kluyveri ARSs require a sequence that is similar but much longer than the ARS Consensus Sequence well defined in Saccharomyces cerevisiae. Moreover, compared with S. cerevisiae and K. lactis, the replication licensing machinery in L. kluyveri seems more tolerant to variations in the ARS sequence composition. It is able to initiate replication from almost all S. cerevisiae ARSs tested and most Kluyveromyces lactis ARSs. In contrast, only about half of the L. kluyveri ARSs function in S. cerevisiae and less than 10% function in K. lactis.


CONCLUSIONS
Our findings demonstrate a replication initiation system with novel features and underscore the functional diversity within the budding yeasts. Furthermore, we have developed new approaches for analyzing biologically functional DNA sequences with ill-defined motifs.
School of Mathematics and Statistics, University of Sydney, Sydney, Australia. bt16@cornell.edu
Ivan
I
Liachko
Emi
E
Tanaka
Katherine
K
Cox
Shau Chee Claire
SC
Chung
Lu
L
Yang
Arael
A
Seher
Lindsay
L
Hallas
Eugene
E
Cha
Gina
G
Kang
Heather
H
Pace
Jasmine
J
Barrow
Maki
M
Inada
Bik-Kwoon
BK
Tye
Uri
U
Keich
D001483:Base Sequence; D015825:Chromosomes, Fungal; D016384:Consensus Sequence; D004261:DNA Replication / Q000235:genetics*; D004271:DNA, Fungal / Q000235:genetics; D014644:Genetic Variation; D007716:Kluyveromyces / Q000235:genetics; D008969:Molecular Sequence Data; D018741:Replication Origin / Q000235:genetics*; D012441:Saccharomyces cerevisiae / Q000235:genetics; D004718:Saccharomycetales / Q000235:genetics*; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA
D004271:DNA, Fungal