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rRNA 2'-O-methyltransferase fibrillarin; 34 kD nucleolar scleroderma antigen (FBL, FIB1, FLRN)
the name derives from the antigen localization in the dense fibrillar component of nucleoli
Function:
- role in pre-rRNA processing
- utilizes the methyl donor S-adenosyl-L-methionine to catalyze the site-specific 2'-hydroxyl methylation of ribose moieties in pre-ribosomal RNA
- site specificity is provided by a guide RNA that base pairs with the substrate
- methylation occurs at a characteristic distance from the sequence involved in base pairing with the guide RNA
- by homology to other fibrillarins, some or all of the N-terminal domain Arg are modified to asymmetric dimethylarginine (DMA)
- interacts with NOLC1 (putative)
- component of box C/D small nucleolar ribonucleoprotein (snoRNP) particles that contain NHP2L1, FBL, NOP5 & NOP56, plus a guide RNA
- associated with the U3 snRNP, U8 snRNP, U13 snRNP, X & Y small nuclear RNAs
- component of several ribosomal & nucleolar protein complexes interacts with PRMT5
Structure: belongs to the fibrillarin family
Compartment:
- nucleus, nucleolus
- fibrillar region of the nucleolus
Pathology:
- antisera from ~8% of humans with scleroderma recognize fibrillarin
- antibodies to fibrillin are seen in young men with scleroderma & minimal joint involvement
- associated with poor outcomes in scleroderma
a) scleroderma complicated by pulmonary hypertension
b) diffuse cutaneous scleroderma
c) scleroderma complicated by myositis
Laboratory:
- fibrillarin Ab in serum
- fibrillarin IgG in serum
Related
scleroderma (diffuse cutaneous systemic sclerosis)
U3-snRNP; U3 small nuclear ribonucleoprotein
General
antigen
methyltransferase
nuclear protein
Properties
SIZE: entity length = 321 aa
MW = 34 kD
COMPARTMENT: cell nucleus
MOTIF: glycine-rich region {8-77}
binding site
SITE: 143-143
FOR-BINDING-OF: S-adenosylmethionine
S-adenosyl-L-methionine binding {172-173}
S-adenosyl-L-methionine binding {191-192}
S-adenosyl-L-methionine binding {216-217}
binding site
SITE: 236-236
FOR-BINDING-OF: S-adenosylmethionine
Helical {274-306}
Database Correlations
OMIM 134795
UniProt P22087
Pfam PF01269
Entrez Gene 2091
Kegg hsa:2091
References
- Clinical Diagnosis & Management by Laboratory Methods,
19th edition, J.B. Henry (ed), W.B. Saunders Co.,
Philadelphia, PA. 1996, pg 1019
- Entrez Gene :accession 2091
- UniProt :accession P22087
- Medical Knowledge Self Assessment Program (MKSAP) 16, 17
American College of Physicians, Philadelphia 2012, 2015
Component-of
U3-snRNP; U3 small nuclear ribonucleoprotein