. Author manuscript; available in PMC: 2015 Mar 26.

Published in final edited form as: Chem Rev. 2014 Jan 8;114(6):3224–3265. doi: 10.1021/cr400496q

Table 1.

Representative classes of RNAs found in a eukaryotic cell

Category	Name	RNA Length (nts)	Function	References^†	Databases	Single molecule References^†
Coding RNA	Messenger RNA (mRNA)	variable	Protein coding	^15,41	^470,471	^{225,233,268,270,278,292,307,315,345,400,423,430,434}
Housekeeping non-coding RNA	Ribosomal RNA (rRNA)	~120-5,000	Translation	^472-474	⁴⁷⁵	³⁴⁵
	Signal Recognition particle RNA	300	Translation	¹⁰⁷	⁴⁷⁶
	Transfer RNA (tRNA)	70-100	Translation	¹⁰⁰	^477,478
	Small nuclear RNA (snRNA)	60-450	Splicing	⁴³		³⁴³
	Small nucleolar (snoRNA)	60-300	RNA editing	⁹²	⁴⁷⁹
	RNase P RNA	~500	tRNA maturation	¹⁰⁵	⁴⁸⁰
	Telomerase RNA	~400-1,300	chromosome extension	^199,200	⁴⁸¹
Small non-coding RNA (< 200-nts)	Hepatitis Delta Virus (HDV) ribozyme	~84	Unknown	^69,71,482
	Hammerhead ribozyme	~100	Unknown	^67,68
	MicroRNA (miRNA)	20-24	Post-transcriptional gene silencing	^{139,143,148,149}	^483-485	^135,454,455
	Small interfering RNA (siRNA)	20-24	Post-transcriptional gene silencing	¹⁴³	^481,485
	DNA-damage response RNA (DDRNA)	20-35	DNA repair	^123,124,177
	PIWI-interacting RNA (piRNA)	24-31	Germline gene silencing	^121,486	⁴⁸⁷
	Circular RNA (circRNA)	variable	miRNA sponge	^159,160
	Primal RNA (priRNA)	22-23	heterochromatin assembly	¹⁷⁴
Mid-sized ncRNA <1 kb	Promoter-associated RNAs (PARs)	variable	Epigenetic gene regulation	¹⁸⁷	⁴⁸¹
Long non-coding NA (> 200-nts)	Long non-coding RNA (lncRNA)	>200	Epigenetic gene regulation	¹⁷⁹	^484,488,489	^188,416-418
Cis-acting ncRNA	5′-UTR	~150	mRNA regulatory element	⁷⁸	⁴⁹⁰
	3′-UTR	~300	mRNA regulatory element	^78,118	⁴⁹⁰
	Introns	Variable (up to thousand)	mRNA regulatory element	⁴⁹¹	⁴⁹²

^†

Representative references. Please refer to the text for a comprehensive list.