Table 2.

Factors involved in rDNA transcription.

Yeast	35S	Human	47S	Function in rRNA transcription	Citation
RNA Polymerase I subunits
Rpb5	x	POLR2E	x	RNAPI subunits, shared with RNAPII and RNAPIII between polymerases	Russell and Zomerdijk (2006)
Rpb6	x	POLR2F	x
Rpb8	x	POLR2H	x
Rpb10	x	POLR2L	x
Rpb12	x	POLR2K	x
Rpa40	x	POLR1C	x	RNAPI subunits, shared with RNAPIII
Rpa19	x	POLR1D	x
Rpa190	x	POLR1A	x	RNAPI‐specific subunits
Rpa135	x	POLR1B	x
Rpa43	x	POLR1F	x
Rpa14	x
Rpa12	x	POLR1H	x
Rpa49	x	POLR1E	x
Rpa34	x	POLR1G	x
PIC formation/promoter escape
Tbp	x	TBP	x	TATA box binding protein	Comai et al (1994)
		UBF	x	Binds rDNA promoter as a dimer, has a role in promoter escape and regulation of elongation	Bell et al (1988)
Rrn3	x	RRN3	x	RNAPI‐specific initiation factor, stimulates RNAPI recruitment	Milkereit and Tschochner (1998)
Rrn6	x	TAF1C	x	Involved in PIC formation. In yeast: part of CF Complex; in humans: part of selectivity factor SL1	Comai et al (1994)
Rrn7	x	TAF1B	x
Rrn11	x	TAF1A	x
		TAF1D	x	Involved in PIC formation: part of human Selectivity factor SL1	Denissov et al (2007) and Gorski et al (2007)
		TAF12	x
Rrn5	x			Involved in PIC formation: part of yeast UAF complex	Keys et al (1996), Keener et al (1997) and Siddiqi et al (2001)
Rrn9	x
Rrn10	x
Uaf30	x
Hht1/H3	x	H3C1/H3
Hhf1/H4	x	H4C1/H4
Top1	x	TOP1	x	Facilitate PIC formation by removing super coils at rDNA promoters and promote elongation	Brill et al (1987) and Ray et al (2013)
Top2	x	TOP2A	x
Cka1		CK2A1	x	Involved in PIC formation; part of tetrameric CK2 complex, regulate interaction between UBF and SL1	Panova et al (2006)
Cka2		CK2A2	x
Ckb1		CK2N	x
Elongation
Spt4	x	SPT4H	x	DSIF complex, influences RNAPI activity; Regulates binding of UBF to rDNA	Schneider et al (2006)
Spt5	x	SPT5H	x
Paf1	x	PAF1	x	Paf1C complex, influences RNAPI activity	Zhang et al (2009)
Ctr9	x	CTR9	x
Cdc73	x	WDR61	x
Rtf1	x	RTF1	x
Leo1	x	LEO1	x
Spt16	x	SUPT16H	x	FACT complex, supports RNAPI transcription through nucleosomes	Birch et al (2009)
Pob3	x	SSRP1	x
Fcp1	x			Dephosphorylates RNAPI for efficient RNA synthesis	Fath et al (2004)
Termination
Rnt1	x			Endonucleolytic cleavage at end of 25S transcript	el Hage et al (2008)
Rat1	x			Release of RNAPI transcribing 3′ part of the transcript	el Hage et al (2008)
Reb1	x	TTF1	x	RNAPI transcription termination factors, bind to termination sequence T1, lead to RNAP I pausing	Reiter et al (2012)
Nsi1	x				Reiter et al (2012)
Fob1	x			Binds to replication fork barrier sequence, inhibits clashes with DNA replication machinery	el Hage et al (2008)
rDNA organization
Hmo1	x			Associates with active rDNA repeats, related to UBF	Gadal et al (2002)
		CTCF	x	Regional organization of rDNA	van de Nobelen et al (2010)
		MYC	x	Attachment of rDNA to nucleolar matrix; local histone acetylation	Grandori et al (2005)
		MAX	x	Interacts with MYC	Nair and Burley (2003)
		TCOF1	x	Facilitates rDNA transcription, interacts with UBF and RNAPI, and is involved in rRNA methylation	Werner et al (2015)
Srp40		NOLC1	x	Interacts with TCOF1	Valdez et al (2004)
Bdf2		BRD2	x	Regulation of RNAPI activity by histone acetylation, recruited by LYAR	Izumikawa et al (2019)
Bdf1		BRD4	x
		KAT7	x
Nto1		JADE3	x
YCR087C		LYAR	x	Binds to UBF, recruits BRD2/4‐KAT7	Izumikawa et al (2019)
Factors acting both in rRNA transcription and early processing steps
		SIRT7	x	Required for the activation of Pol I transcription at the exit from mitosis	Ford et al (2006) and Iyer‐Bierhoff et al (2018)
Nop1		FBL	x	Methylates rRNA and histone H2AQ104	Tessarz et al (2014)
Utp4		UTP4	x	t‐UTPs, function in both rRNA transcription and the SSU processome	Gallagher et al (2004) and Prieto and McStay (2007)
Utp5		WDR43/UTP5	x
Utp10		HEATR1/UTP10	x
Utp15		UTP15	x
Utp17		UTP17/WDR75	x