A history of the Sm/Lsm-SmAP-Hfq family. Human Sm proteins were discovered over 30 y ago as a group of small antigens involved in the autoimmune disease systemic lupus erythematosus. The ≈80-residue proteins were identified in association with ribonucleoprotein (RNP) complexes from eukaryotic cellular extracts. Other early work uncovered vital roles for Sm proteins in forming the cores of the u...

Introduction Quiescent and dormant embryos, germination: definitions Nuclear characteristics of the cell population in quiescent embryos Distribution of quiescent embryo cell nuclei in different phases of the cell cycle How is the high G\ cell level of quiescent embryos established? What are the mechanisms controlling G\ cell accumulation? Controversial observations on the high G\ accumulation ...

Group II introns are mobile retroelements that self-splice from precursor RNAs to form ribonucleoparticles (RNP), which can invade new specific genomic DNA sites. This specificity can be reprogrammed, for insertion into any desired DNA site, making these introns useful tools for bacterial genetic engineering. However, previous studies have suggested that these elements may function inefficientl...

R NA molecules stowed in cytoplasmic granules are generally thought to be silent. But a protein mutated in some amyotrophic lateral sclerosis (ALS) patients forms granules that permit translation of stored RNAs, Yasuda et al. reveal (1). The fi nding identifi es a new mechanism that could contribute to the pathology of the disease and suggests that RNAs in other types of granules also may not b...

Humans express four distinct non-protein-coding Y RNAs (ncRNAs). To investigate Y RNA functional diversification, we exploited an RNA-based affinity purification method to isolate ribonucleoproteins (RNPs) assembled on individual human Y RNAs. Silver staining and mass spectrometry revealed that the Ro and La proteins assemble with all Y RNAs, while additional proteins associate with specific Y ...

Influenza A virus is an enveloped virus with a segmented, single-strand, negative-sense RNA genome. Its virions show spherical or filamentous shapes of about 100 nm in diameter and occasionally irregular morphology, which exemplifies the pleomorphic nature of these virions. Each viral RNA segment forms a ribonucleoprotein complex (RNP), along with an RNA-dependent RNA polymerase complex and mul...

Messenger RNA localization involves the assembly of ribonucleoprotein particles (RNPs) and their subsequent transport along the cytoskeleton to their final destination. Here, we provide new evidence that microtubule-associated protein 2 (MAP2), calcium/ calmodulin-dependent protein kinase II (CaMKIIa) and b-actin RNAs localize to dendrites in distinct RNPs, which contain— unexpectedly—very few ...

The survival motor neuron (SMN) complex functions in maturation of uridine-rich small nuclear ribonucleoprotein (RNP) particles. SMN mediates the cytoplasmic assembly of Sm proteins onto uridine-rich small RNAs, and then participates in targeting RNPs to nuclear Cajal bodies (CBs). Recent studies have suggested that phosphorylation might control localization and function of the SMN complex. Her...