PT  - JOURNAL ARTICLE
AU  - Dundr, Miroslav
AU  - Hoffmann-Rohrer, Urs
AU  - Hu, Qiyue
AU  - Grummt, Ingrid
AU  - Rothblum, Lawrence I.
AU  - Phair, Robert D.
AU  - Misteli, Tom
TI  - A Kinetic Framework for a Mammalian RNA Polymerase in Vivo
AID  - 10.1126/science.1076164
DP  - 2002 Nov 22
TA  - Science
PG  - 1623--1626
VI  - 298
IP  - 5598
4099  - http://science.sciencemag.org/content/298/5598/1623.short
4100  - http://science.sciencemag.org/content/298/5598/1623.full
SO  - Science2002 Nov 22; 298
AB  - We have analyzed the kinetics of assembly and elongation of the mammalian RNA polymerase I complex on endogenous ribosomal genes in the nuclei of living cells with the use of in vivo microscopy. We show that components of the RNA polymerase I machinery are brought to ribosomal genes as distinct subunits and that assembly occurs via metastable intermediates. With the use of computational modeling of imaging data, we have determined the in vivo elongation time of the polymerase, and measurements of recruitment and incorporation frequencies show that incorporation of components into the assembling polymerase is inefficient. Our data provide a kinetic and mechanistic framework for the function of a mammalian RNA polymerase in living cells.