The Reb1-homologue Ydr026c/Nsi1 is required for efficient RNA polymerase I termination in yeast.
Several DNA cis-elements and trans-acting factors were described to be involved in transcription termination and to release the elongating RNA polymerases from their templates. Different models for the molecular mechanism of transcription termination have been suggested for eukaryotic RNA polymerase I (Pol I) from results of in vitro and in vivo experiments. To analyse the molecular requirements for yeast RNA Pol I termination, an in vivo approach was used in which efficient termination resulted in growth inhibition. This led to the identification of a Myb-like protein, Ydr026c, as bona fide termination factor, now designated Nsi1 (NTS1 silencing protein 1), since it was very recently described as silencing factor of ribosomal DNA. Possible Nsi1 functions in regard to the mechanism of transcription termination are discussed.
Universität Regensburg, Biochemie-Zentrum Regensburg (BZR), Lehrstuhl Biochemie III, Regensburg, Germany.
Alarich
A
Reiter
Stephan
S
Hamperl
Hannah
H
Seitz
Philipp
P
Merkl
Jorge
J
Perez-Fernandez
Lydia
L
Williams
Jochen
J
Gerber
Attila
A
Németh
Isabelle
I
Léger
Olivier
O
Gadal
Philipp
P
Milkereit
Joachim
J
Griesenbeck
Herbert
H
Tschochner
D000595:Amino Acid Sequence; D004268:DNA-Binding Proteins / Q000378:metabolism*; D008969:Molecular Sequence Data; D012318:RNA Polymerase I / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000254:growth & development / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D014158:Transcription, Genetic
D004268:DNA-Binding Proteins; C574300:Nsi1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D012318:RNA Polymerase I