Human U1 snRNA forms a new chromatin-associated snRNP with TAF15.
The U1 small nuclear RNA (snRNA)--in the form of the U1 spliceosomal Sm small nuclear ribonucleoprotein particle (snRNP) that contains seven Sm and three U1-specific RNP proteins-has a crucial function in the recognition and removal of pre-messenger RNA introns. Here, we show that a fraction of human U1 snRNA specifically associates with the nuclear RNA-binding protein TBP-associated factor 15 (TAF15). We show that none of the known protein components of the spliceosomal U1-Sm snRNP interacts with the newly identified U1-TAF15 snRNP. In addition, the U1-TAF15 snRNP tightly associates with chromatin in an RNA-dependent manner and accumulates in nucleolar caps upon transcriptional inhibition. The Sm-binding motif of U1 snRNA is essential for the biogenesis of both U1-Sm and U1-TAF15 snRNPs, suggesting that the U1-TAF15 particle is produced by remodelling of the U1-Sm snRNP. A demonstration that human U1 snRNA forms at least two structurally distinct snRNPs supports the idea that the U1 snRNA has many nuclear functions.
Jobert
Laure
L
Institut de Génétique et de Biologie Moléculaire et Cellulaire, Department of Functional Genomics, CNRS UMR 7104, INSERM U 964, Université de Strasbourg, 1 Rue Laurent Fries, BP 10142, 67404 Illkirch, France.
Pinzón
Natalia
N
Van Herreweghe
Elodie
E
Jády
Beáta E
BE
Guialis
Apostolia
A
Kiss
Tamás
T
Tora
László
L
D001483:Base Sequence; D015153:Blotting, Western; D002843:Chromatin / Q000235:genetics / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D006367:HeLa Cells; D006801:Humans; D047468:Immunoprecipitation; D017403:In Situ Hybridization; D011485:Protein Binding; D012342:RNA, Small Nuclear / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D035381:TATA-Binding Protein Associated Factors / Q000378:metabolism*
D002843:Chromatin; D012342:RNA, Small Nuclear; C102041:TAF15 protein, human; D035381:TATA-Binding Protein Associated Factors; C405483:U1 small nuclear RNA