RNA polymerase 1

Function

• synthesis of rRNA
• transcription of ribosomal RNA genes, present in tandem repeats
• synthesizes ribosomal RNA precursors

Structure

• consists of at least 13 subunits
• pol 1 is composed of mobile elements & a core element with a central large cleft & probably a clamp element that moves to open & close the cleft (putative)
• a bridging helix emanates from POLR1A & crosses the cleft near the catalytic site & is thought to promote translocation of pol 1 by acting as a ratchet that moves the RNA-DNA hybrid through the active site by switching from straight to bent conformations at each step of nucleotide addition (putative)

Compartment

nucleus, nucleolus

More general terms

• RNA polymerase

Components

• RNA polymerases 1, 2, & 3 subunit RPABC2 (RPB6, RNA polymerase 2 subunit F, POLR2F, POLRF, ABC2, RPABC14.4, RPB14.4, RPC15)
• RNA polymerases 1, 2, & 3 subunit RPABC1 (RNA polymerases 1, 2, & 3 subunit ABC1, RNA polymerase 2 23 kD subunit, RNA polymerase 2 subunit E, RNA polymerase 2 subunit 5, POLR2E, RPABC1, RPB25, RBP5, XAP4)