there was less contamination of the messenger ribonucleoprotein species prepared by this method than by EDTA dissociation. No major qualitative differences were observed between the proteins present in the particles obtained from free and membrane-bound polyribosomes. The results described here demonstrate the presence in tendon cells of polyribosomal messenger ribonucleoprotein particles whose...

Most scholars regard mixed connective tissue disease (MCTD) to be a separate illness, whereas some suggest it might precursor distinct disease, such as SLE, SSc, or overlap syndrome. There are no clinical symptoms of MCTD, and presentations vary greatly across individuals. Since the first description, categorization entity has been debated, particularly because individuals with U1 small nuclear...

Nop56p is a component of the box C/D small nucleolar ribonucleoprotein complexes that direct 2'-O-methylation of pre-rRNA during its maturation. Genetic analyses in yeast have shown that Nop56p plays important roles in the early steps of pre-rRNA processing. However, its precise function remains elusive, especially in higher eukaryotes. Here we describe the proteomic characterization of human N...

In Drosophila oocytes and neuroblasts, the double-stranded RNA binding protein Staufen assembles into ribonucleoprotein particles, which mediate cytoplasmic mRNA trafficking and translation. Two different mammalian orthologues also appear to reside in distinct RNA-containing particles. To date, relatively little is known about the molecular composition of Staufen-containing ribonucleoprotein co...

As in higher eukaryotes, heterogeneous nuclear RNA (HNRNA) in the cellular slime mold Dictyostelium discoideum is associated with proteins in the form of ribonucleoprotein particles. Mixing experiments with deproteinized hnRNA establish that the nuclear ribonucleoprotein particles are not formed artificially during isolation. In contrast to comparable material from mammalian cells (polydisperse...

We have achieved a high degree of purification of nuclear ribonucleoprotein antigen from calf thymus nuclear extract through antibody affinity chromatography. Antibody to nuclear ribonucleoprotein was purified from the serum of a patient with mixed connective tissue disease and Sepharose 4B was covalently coupled with the purified human antibody. The sodium thiocyanate eluate from the affinity ...

Recently, a number of novel small cytoplasmic ribonucleoprotein particles have been identified that comprise RNA and protein subunits related to the signal recognition particle (SRP). Here we discuss the latest results on the structure and functions of SRP together with the structures and putative functions of the novel SRP-related ribonucleoprotein particles.