Biogenesis of small nuclear RNPs

Biogenesis of small nuclear RNPs.

The nucleus contains a large number of metabolically stable, 60-450-nt-long small nuclear RNAs (snRNAs) that exist in the form of ribonucleoproteins (snRNPs) (Yu et al., 1999). Each snRNP is composed of an snRNA and a set of associated RNP proteins. Based on their function and intranuclear localization, mammalian snRNPs can be classified into three major classes. The U1, U2, U4, U5 and U6 major...

Splicing-independent recruitment of spliceosomal small nuclear RNPs to nascent RNA polymerase II transcripts

In amphibian oocytes, most lateral loops of the lampbrush chromosomes correspond to active transcriptional sites for RNA polymerase II. We show that newly assembled small nuclear ribonucleoprotein (RNP [snRNP]) particles, which are formed upon cytoplasmic injection of fluorescently labeled spliceosomal small nuclear RNAs (snRNAs), target the nascent transcripts of the chromosomal loops. With th...

Biogenesis of nuclear bodies.

The nucleus is unique amongst cellular organelles in that it contains a myriad of discrete suborganelles. These nuclear bodies are morphologically and molecularly distinct entities, and they host specific nuclear processes. Although the mode of biogenesis appears to differ widely between individual nuclear bodies, several common design principles are emerging, particularly, the ability of nucle...

Synthesis and Assembly of the Box C1D Small Nucleolar RNPs

Nuclear pore complex biogenesis.

Nuclear pore complexes (NPCs) are the sole mediators of transport between the nucleus and the cytoplasm. NPCs have a life cycle: they assemble, disassemble, turnover, and age. The molecular mechanisms governing these different vital steps are beginning to emerge, suggesting key roles for the core structural scaffold of the NPC and auxiliary factors in the assembly of this large macromolecular c...