A general cloning system to selectively isolate any eukaryotic or prokaryotic genomic region in yeast.
BACKGROUND
Transformation-associated recombination (TAR) cloning in yeast is a unique method for selective isolation of large chromosomal fragments or entire genes from complex genomes. The technique involves homologous recombination, during yeast spheroplast transformation, between genomic DNA and a TAR vector that has short (approximately 60 bp) 5' and 3' gene targeting sequences (hooks).


RESULTS
TAR cloning requires that the cloned DNA fragment carry at least one autonomously replicating sequence (ARS) that can function as the origin of replication in yeast, which prevents wide application of the method. In this paper, we describe a novel TAR cloning system that allows isolation of genomic regions lacking yeast ARS-like sequences. ARS is inserted into the TAR vector along with URA3 as a counter-selectable marker. The hooks are placed between the TATA box and the transcription initiation site of URA3. Insertion of any sequence between hooks results in inactivation of URA3 expression. That inactivation confers resistance to 5-fluoroorotic acid, allowing selection of TAR cloning events against background vector recircularization events.


CONCLUSIONS
The new system greatly expands the area of application of TAR cloning by allowing isolation of any chromosomal region from eukaryotic and prokaryotic genomes regardless of the presence of autonomously replicating sequences.
Noskov
Vladimir N
VN
Laboratory of Biosystems and Cancer, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA. noskovv@mail.nih.gov
Kouprina
Natalay
N
Leem
Sun-Hee
SH
Ouspenski
Ilia
I
Barrett
J Carl
JC
Larionov
Vladimir
V
D000818:Animals; D002503:Centromere / Q000235:genetics; D018244:Chromosomes, Artificial, Yeast / Q000235:genetics; D003001:Cloning, Molecular / Q000379:methods*; D005057:Eukaryotic Cells / Q000737:chemistry / Q000378:metabolism; D005822:Genetic Vectors / Q000235:genetics; D016681:Genome, Fungal; D015894:Genome, Human; D006801:Humans; D007041:Hypoxanthine Phosphoribosyltransferase / Q000235:genetics; D051379:Mice; D015689:Oncogene Protein p21(ras) / Q000235:genetics; D011387:Prokaryotic Cells / Q000737:chemistry / Q000378:metabolism; D018741:Replication Origin / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000737:chemistry / Q000235:genetics*; D013104:Spheroplasts / Q000235:genetics; D014170:Transformation, Genetic / Q000235:genetics
D007041:Hypoxanthine Phosphoribosyltransferase; D015689:Oncogene Protein p21(ras)