RLR1 (THO2), required for expressing lacZ fusions in yeast, is conserved from yeast to humans and is a suppressor of SIN4.
We isolated a mutation (rlr1-1; required for lacZ RNA) in the Saccharomyces cerevisiae (Sc) RLR1 gene as a suppressor of sin4, a component of the Mediator subcomplex of the RNA polymerase II holoenzyme and a determinant of chromatin structure. RLR1 encodes a deduced protein found also in fission yeast, nematode worms, and humans. The presence of these orthologs suggests that Rlr1 family members comprise a class of putative KEKE motif-containing proteins, characteristic of certain chaperones as well as regulators and subunits of the mammalian 20S proteasome. A role for RLR1 (THO2) in transcription appears to occur at a step subsequent to transcription initiation (see also Piruat, J.I. and Aguilera, A., 1998. EMBO J. 17, 4859-4872); Sc genes fused to the reporter gene lacZ were expressed at a very low level, while the corresponding native chromosomal genes were expressed at approximately normal levels in rlr1 mutants. Our studies show that rlr1 mutations cause a wide range of growth defects in addition to their novel affect on lacZ.
West
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RW
Department of Biochemistry, State University of New York, Health Science Center at Syracuse, Syracuse, NY, USA.
Kruger
B
B
Thomas
S
S
Ma
J
J
Milgrom
E
E
D000595:Amino Acid Sequence; D002455:Cell Division / Q000235:genetics; D003001:Cloning, Molecular; D017124:Conserved Sequence; D003574:Cytochrome c Group / Q000235:genetics; D045304:Cytochromes c; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics; D005656:Fungal Proteins / Q000235:genetics* / Q000502:physiology; D015966:Gene Expression Regulation, Fungal / Q000502:physiology; D006801:Humans; D007763:Lac Operon / Q000235:genetics*; D056892:Mediator Complex; D008969:Molecular Sequence Data; D009154:Mutation; D010802:Phylogeny; D011993:Recombinant Fusion Proteins / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000254:growth & development; D029701:Saccharomyces cerevisiae Proteins; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D013172:Spores, Fungal / Q000235:genetics; D015534:Trans-Activators; D014157:Transcription Factors / Q000235:genetics*
C014059:CYC1 protein, S cerevisiae; D003574:Cytochrome c Group; D004271:DNA, Fungal; D005656:Fungal Proteins; D056892:Mediator Complex; D011993:Recombinant Fusion Proteins; C076878:SIN4 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C405934:THO2 protein, S cerevisiae; D015534:Trans-Activators; D014157:Transcription Factors; D045304:Cytochromes c