|
General Comment |
Fibrillarin, not to be confused with fibrillin , is a component of a nucleolar small nuclear ribonucleoprotein
(snRNP) particle thought to participate in the first step in processing preribosomal RNA. In humans, fibrillarin is associated with the U3, U8, and U13 small nuclear RNAs.
NCBI Summary:
This gene product is a component of a nucleolar small nuclear ribonucleoprotein (snRNP) particle thought to participate in the first step in processing preribosomal RNA. It is associated with the U3, U8, and U13 small nuclear RNAs and is located in the dense fibrillar component (DFC) of the nucleolus. The encoded protein contains an N-terminal repetitive domain that is rich in glycine and arginine residues, like fibrillarins in other species. Its central region resembles an RNA-binding domain and contains an RNP consensus sequence. Antisera from approximately 8% of humans with the autoimmune disease scleroderma recognize fibrillarin. [provided by RefSeq, Jul 2008]
|
|
Comment |
Fibrillarin-GFP Facilitates the Identification of Meiotic Competent Oocytes. [Wang T et al. (2021)$33937243] The nucleolus undergoes significant functional changes and plays important roles during mammalian oocyte meiotic maturation. Fibrillarin (FBL) is the component of nucleolar small nuclear ribonucleoprotein (snRNP) particle and localizes to the dense fibrillar component (DFC) of the nucleolus. We found that FBL-GFP displays an uneven and cloudy localization in the nucleolus of non-surrounded nucleolus (NSN) oocytes, while it distributes evenly and to a few bright dots in the surrounded nucleolus (SN) oocytes. Accordingly, NSN oocytes showed active nascent RNA transcription, while the SN group was transcriptionally quiescent. NSN geminal vesicles also contained more DNA damage marker γH2AX foci. Based on different FBL-GFP patterns in live oocytes, the ones with superior meiotic maturation potential can be identified. Global transcriptome profiling revealed a significant difference in single SN and NSN oocytes. Thus, FBL-GFP can serve as a marker for nucleolus activity, which also correlates with transcription activity and the quality of oocytes.//////////////////
Trudee Fair et al 2001 reported the immunolocalization of Nucleolar Proteins During
Bovine Oocyte Growth, Meiotic Maturation, and
Fertilization.
During the growth phase of the bovine oocyte transcripts, polypeptides and ribosomes are accumulated in the oocyte to
drive and sustain future meiotic maturation, fertilization, and early embryonic development. The oocyte also furnishes
the early embryo with the components required to establish a functional transcriptionally active nucleolus at the time of
maternal embryonic transition. The temporal localization of nucleolar proteins fibrillarin, nucleophosmin, nucleolin, RNA polymerase I (RNA pol I), upstream binding factor (UBF), and coilin 5P10 was investigated in growing and fully
grown immature bovine oocytes during in vitro maturation and during the first postfertilization cell cycle using
whole-mount immunocytochemistry and confocal microscopy. During the oocyte growth phase, fibrillarin,
nucleophosmin, nucleolin, RNA pol I, and UBF were localized to the oocyte nucleolus. On completion of the growth phase, nucleolin and nucleophosmin appeared to migrate to the periphery of the nucleolus and into the nucleoplasm, and
the proportion of oocytes displaying RNA pol I localization had decreased. Fibrillarin appeared to be localized to large foci within the nucleolus and/or nucleoplasm. Nucleophosmin and
nucleolin labeling was characterized by a homogenous signal over the nucleolus. RNA pol I and UBF were
characterized by the localization of the antibodies to individual or clustered foci in the nucleolus and/or nucleoplasm.
Following oocyte nucleus breakdown (ONBD), the proteins appeared to disperse into the cytoplasm.
|