Ribonuclease H(70) is a component of the yeast nuclear scaffold.
We have used monospecific antibodies against three ribonuclease H enzymes of Saccharomyces cerevisiae to investigate their intracellular localization. Fractionation experiments, as well as immunocytochemical staining, revealed a predominantly cytoplasmic localization of the RNase H proteins of 42,000 and 70,000 Mr, whereas that of 55,000 Mr showed equal distribution between nuclei and cytoplasm. The nuclear moiety of ribonuclease H(70) was found to be a part of the yeast nuclear scaffold, as investigated by immunoblotting and antibody inhibition experiments. The 42,000 and 55,000 Mr enzymes, on the other hand, are not scaffold-associated. We conclude that RNase H(70) is part of the nuclear substructure of yeast that was previously found to maintain specific interactions with yeast chromosomal origins of replication (ARS elements).
Karwan
R M
RM
Institute of Tumorobiology-Cancer Research, University of Vienna, Austria.
Laroche
T
T
Wintersberger
U
U
Gasser
S M
SM
Binder
M
M
D002467:Cell Nucleus / Q000201:enzymology / Q000648:ultrastructure; D003593:Cytoplasm / Q000378:metabolism; D004722:Endoribonucleases / Q000378:metabolism*; D007150:Immunohistochemistry; D016253:Microscopy, Immunoelectron; D008970:Molecular Weight; D016914:Ribonuclease H; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000648:ultrastructure
D004722:Endoribonucleases; D016914:Ribonuclease H