TY - JOUR
T1 - The 2μm-plasmid-encoded Rep1 and Rep2 proteins interact with each other and colocalize to the Saccharomyces cerevisiae nucleus
AU - Ahn, Yong Tae
AU - Wu, Xu Li
AU - Biswal, Shyam
AU - Velmurugan, Soundarapandian
AU - Volkert, Frederic C.
AU - Jayaram, Makkuni
PY - 1997/12
Y1 - 1997/12
N2 - The efficient partitioning of the 2μm plasmid of Saccharomyces cerevisiae at cell division requires two plasmid-encoded proteins (Rep1p and Rep2p) and a cis-acting locus, REP3 (STB). By using protein hybrids containing fusions of the Rep proteins to green fluorescent protein (GFP), we show here that fluorescence from GFP-Rep1p or GFP-Rep2p is almost exclusively localized in the nucleus in a cir+ strain. Nuclear localization of GFP- Rep1p and GFP-Rep2p, though discernible, is less efficient in a cir°host. GFP-Rep2p or GFP-Rep1p is able to promote the stability of a 2μm circle- derived plasmid harboring REP1 or REP2, respectively, in a cir°background. Under these conditions, fluorescence from GFP-Rep2p or GFP-Rep1p is concentrated within the nucleus, as is the case in cir+ cells. This characteristic nuclear accumulation is not dependent on the expression of the FLP or RAF1 gene of the 2μm circle. Nuclear colocalization of Rep1p and Rep2p is consistent with the hypothesis that the two proteins directly or indirectly interact to form a functional bipartite or high-order protein complex. Immunoprecipitation experiments as well as baiting assays using GST- Rep hybrid proteins suggest a direct interaction between Rep1p and Rep2p which, in principle, may be modulated by other yeast proteins. Furthermore, these assays provide evidence for Rep1p-Rep1p and Rep2p-Rep2p associations as well. The sum of these interactions may be important in controlling the effective cellular concentration of the Rep1p-Rep2p complex.
AB - The efficient partitioning of the 2μm plasmid of Saccharomyces cerevisiae at cell division requires two plasmid-encoded proteins (Rep1p and Rep2p) and a cis-acting locus, REP3 (STB). By using protein hybrids containing fusions of the Rep proteins to green fluorescent protein (GFP), we show here that fluorescence from GFP-Rep1p or GFP-Rep2p is almost exclusively localized in the nucleus in a cir+ strain. Nuclear localization of GFP- Rep1p and GFP-Rep2p, though discernible, is less efficient in a cir°host. GFP-Rep2p or GFP-Rep1p is able to promote the stability of a 2μm circle- derived plasmid harboring REP1 or REP2, respectively, in a cir°background. Under these conditions, fluorescence from GFP-Rep2p or GFP-Rep1p is concentrated within the nucleus, as is the case in cir+ cells. This characteristic nuclear accumulation is not dependent on the expression of the FLP or RAF1 gene of the 2μm circle. Nuclear colocalization of Rep1p and Rep2p is consistent with the hypothesis that the two proteins directly or indirectly interact to form a functional bipartite or high-order protein complex. Immunoprecipitation experiments as well as baiting assays using GST- Rep hybrid proteins suggest a direct interaction between Rep1p and Rep2p which, in principle, may be modulated by other yeast proteins. Furthermore, these assays provide evidence for Rep1p-Rep1p and Rep2p-Rep2p associations as well. The sum of these interactions may be important in controlling the effective cellular concentration of the Rep1p-Rep2p complex.
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U2 - 10.1128/jb.179.23.7497-7506.1997
DO - 10.1128/jb.179.23.7497-7506.1997
M3 - Article
C2 - 9393716
AN - SCOPUS:0030613797
SN - 0021-9193
VL - 179
SP - 7497
EP - 7506
JO - Journal of bacteriology
JF - Journal of bacteriology
IS - 23
ER -