Table 2. Loss-of-function phenotypes of genes discussed in this review.

Loss-of-function phenotypes
Gene	Superficially wild-type	Sterile	Lethal	Increased germ line apoptosis	L1 arresta	synMuv	Increased mutation rate	Somatic expression of germ line genes	Heterochromatic array desilencing	Other phenotypes	References
Histone methyltransferases
met-2	x	mrt		x		x		x	Yes	Satellite repeat transcription	Poulin et al. (2005), Andersen and Horvitz (2007), Bessler et al. (2010), Koester-Eiserfunke and Fischle (2011), Towbin et al. (2012), Wu et al. (2012), Zeller et al. (2016), J. Padeken, P. Zeller, and S. M. Gasser, (unpublished results)
set-25	x						x		Yes	Retrotransposon expression	Pothof et al. (2003), Andersen and Horvitz (2007), Towbin et al. (2012), Zeller et al. (2016), McMurchy et al. (2017), J. Padeken, P. Zeller, and S. M. Gasser, (unpublished results)
set-32	x	mrt								Nuclear RNAi and piRNA pathway effector	Andersen and Horvitz (2007), Ashe et al. (2012), Kalinava et al. (2017), Spracklin et al. (2017)
set-1		ste								Dosage compensation defect	Vielle et al. (2012), Wells et al. (2012), Kramer et al. (2016)
set-4	x										Vielle et al. (2012), Wells et al. (2012), Kramer et al. (2016)
mes-4		mes							Yes	synMuv suppressor	Capowski et al. (1991), Cui et al. (2006), Towbin et al. (2012)
met-1	x					x			No		Andersen and Horvitz (2007), Towbin et al. (2012), Wu et al. (2012)
met-2 set-25	x	mrt		x			x		Yes	Loss of heterochromatin anchoring; repeat element expression	Towbin et al. (2012), Zeller et al. (2016), McMurchy et al. (2017)
PRC2-like complex
mes-2		mes								Yes	Capowski et al. (1991), Towbin et al. (2012)
mes-3		mes								Yes	Capowski et al. (1991), Towbin et al. (2012)
mes-6		mes								Yes	Capowski et al. (1991), Towbin et al. (2012)
Histone demethylases
spr-5	x	mrt									Katz et al. (2009), Greer et al. (2016)
jmjd-1.2	x									Locomotion; mitochondrial stress-induced longevity defect; DNA repair defect	Lee et al. (2015), Merkwirth et al. (2016), Riveiro et al. (2017)
jmjd-3.1										Abnormal gonad development; transdifferentiation defect	Agger et al. (2007), Zuryn et al. (2014)
utx-1		steb				x					Wang et al. (2010), Vandamme et al. (2012)
Heterochromatin-associated proteins
hpl-1	x										Schott et al. (2006)
hpl-2		stec		x	x	x		x	Yes		Capowski et al. (1991), Couteau et al. (2002), Wang et al. (2005), Schott et al. (2006), Petrella et al. (2011), Towbin et al. (2012), Wu et al. (2012), McMurchy et al. (2017)
cec-3	x									Suppresses spr-5 Transgenerational sterility; unc-4 ectopic expression	Zheng et al. (2013), Greer et al. (2014)
cec-4	x								No	Loss of perinuclear chromatin anchoring	Gonzalez-Sandoval et al. (2015)
lin-61	x			x	x	x	x	x	Yes	Compromised homology-driven repair	Pothof et al. (2003), Poulin et al. (2005), Harrison et al. (2007), Koester-Eiserfunke and Fischle (2011), Petrella et al. (2011), Towbin et al. (2012), Wu et al. (2012), Johnson et al. (2013), McMurchy et al. (2017)
lin-13		ste		x	x	x		x	Yes		Ferguson and Horvitz (1985), Melendez and Greenwald (2000), Wang et al. (2005), Petrella et al. (2011), Wu et al. (2012), McMurchy et al. (2017)
let-418		ste			x	x		x	No		Solari and Ahringer (2000), von Zelewsky et al. (2000), Unhavaithaya et al. (2002), Passannante et al. (2010), Wu et al. (2012)
Small RNA pathway proteins
prg-1	x	mrt		x							Batista et al. (2008), Das et al. (2008), Simon et al. (2014), McMurchy et al. (2017)
nrde-1	x	mrt							Yes		Burkhart et al. (2011), Buckley et al. (2012), J. Padeken, P. Zeller, and S. M. Gasser, (unpublished results)
nrde-2	x	mrt									Guang et al. (2010), Buckley et al. (2012)
nrde-3	x	mrt							Yes		Guang et al. (2008), J. Padeken, P. Zeller, and S. M. Gasser, (unpublished results)
nrde-4	x	mrt									Burkhart et al. (2011), Buckley et al. (2012), J. Padeken, P. Zeller and S. M. Gasser, (unpublished results)
hrde-1	x	mrt									Ashe et al. (2012), Buckley et al. (2012), Luteijn et al. (2012), Shirayama et al. (2012)
morc-1	x	mrt									Spracklin et al. (2017), Weiser et al. (2017)

Common phenotypes observed in chromatin-modulating mutants are listed. Phenotypes listed are not comprehensive and were not assessed in all mutants. synMuv, synthetic multivulval; mrt, mortal germ line (transgenerationally sterile); RNAi, RNA interference; piRNA, piwi-interacting RNA; ste, zygotic sterile; mes, maternal-effect sterile.

^aSome mutants undergo L1 arrest only at high temperature (26°).

^bHomozygotes are nearly sterile, and the few embryos produced die.

^cNull mutant is sterile at 25°.

^dCo-RNAi or double mutant of lem-2 and emr-1 is lethal.