Snrpn, Snurf, IPW, MBII-436, MBII-13, Pwcr1 (MBII-85), MBII-52, Ube3a-AS
Large alternatively spliced transcripts (Large paternal Non-Coding RNA, LNCAT) extend from (U) exons
upstream of Snurf/Snrpn to the Ube3a antisense region (Landers
M et al, 2004; Le
Meur E et al, 2005).
These transcripts are paternally expressed and include Snurf, Snrpn, MBII-436 (Ding
F et al, 2005), MBII-13, Pwcr1 (MBII-85), MBII-52, and other components such as the Ipw exons.
Snrpn (small nuclear ribonucleoprotein-associated polypeptide N) and Snurf are two proteins encoded
by the extended Snurf-Snrpn transcript. They are paternally expressed (Leff
SE et al, 1992; Gray
TA et al, 1999).
MBII-13 is a class C/D box small nucleolar RNA (snoRNA) (Cavaille
J et al, 2000).
Pwrcr1 (MBII-85) contains multiple copies of the class C/D box small nucleolar RNAs (snoRNAs)
MBII-85 (equivalent to human SNORD116@ cluster). It is paternally expressed in brain (Cavaille
J et al, 2000; de
los Santos T et al, 2000). Deletion of murine MBII-85 snoRNA caused postnatal growth
retardation, with about 15% postnatal lethality indicating a functional role for a role for the
MBII-85 snoRNA (Skryabin
BV et al 2007).
MBII-52 are class C/D box small nucleolar RNAs (snoRNAs) encoded by multiple copies of a tandem
repeat between adjacent to IPW and it is paternally expressed in brain (Cavaille
J et al, 2000).
Ube3a-AS (Ube3a-ATS) transcripts silence the paternal copy of Ube3a in the brain (Chamberlain
SJ and Brannan CI, 2001; Landers
M et al, 2004).
Ipw (Imprinted in Prader-Willi) is paternally expressed but probably untranslated (Wevrick
R et al, 1997). It is not clear whether IPW has any specific function or whether it is merely
part of the extended transcript.
General reference: (Nicholls
RD and Knepper JL, 2001).
Bisulfite sequencing revealed that reactivation of maternal
alleles of Snrpn in specific tissues was accompanied by partial demethylation at their potential
imprinting control regions (Shi
W et al, 2005).