Biomaterial Database

Polypeptides of nonpolyribosomal messenger ribonucleoprotein complexes of sea urchin eggs. 1980

R T Moon, and K D Moe, and M B Hille

RNA competent in directing protein synthesis is sequestered in unfertilized sea urchin eggs as translationally quiescent, nonpolyribosomal, messenger ribonucleoprotein complexes (mRNPs). Following fertilization, these mRNPs are derepressed and actively translated, presumably due to changes in the mRNA-associated proteins and their interaction with the mRNA. We have isolated poly(A)-containing egg mRNPs free of contaminating monoribosomes and ribosomal subunits by chromatography on oligo(dT)-cellulose and identified their constituent proteins. Egg mRNPs isolated by using near physiological ionic conditions have 15-20 major proteins, most of which are in the molecular weight range of 40 000-100 000, and approximately 15-23 minor proteins in the 22 000-190 000 molecular range. The association of the proteins with poly(A)-containing mRNA is indicated by their greatly reduced retention on oligo(dT)-cellulose after pretreatment of the crude mRNP fraction with saturating amounts of poly(uridylic acid). Three of the proteins present in poly(A)-containing mRNPs from eggs, with molecular weights of 48 000, 67 000, and 140 000, were not detected in poly(A)-containing mRNPs derived from polyribosomes of hatched blastula-stage embryos. In addition, stoichiometric differences were found between some of the proteins associated with the two types of mRNP. The potential regulatory role of these proteins is discussed.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008970	Molecular Weight	The sum of the weight of all the atoms in a molecule.	Molecular Weights,Weight, Molecular,Weights, Molecular
D009693	Nucleic Acid Hybridization	Widely used technique which exploits the ability of complementary sequences in single-stranded DNAs or RNAs to pair with each other to form a double helix. Hybridization can take place between two complimentary DNA sequences, between a single-stranded DNA and a complementary RNA, or between two RNA sequences. The technique is used to detect and isolate specific sequences, measure homology, or define other characteristics of one or both strands. (Kendrew, Encyclopedia of Molecular Biology, 1994, p503)	Genomic Hybridization,Acid Hybridization, Nucleic,Acid Hybridizations, Nucleic,Genomic Hybridizations,Hybridization, Genomic,Hybridization, Nucleic Acid,Hybridizations, Genomic,Hybridizations, Nucleic Acid,Nucleic Acid Hybridizations
D009698	Nucleoproteins	Proteins conjugated with nucleic acids.	Nucleoprotein
D010063	Ovum	A mature haploid female germ cell extruded from the OVARY at OVULATION.	Egg,Egg, Unfertilized,Ova,Eggs, Unfertilized,Unfertilized Egg,Unfertilized Eggs
D010452	Peptide Biosynthesis	The production of PEPTIDES or PROTEINS by the constituents of a living organism. The biosynthesis of proteins on RIBOSOMES following an RNA template is termed translation (TRANSLATION, GENETIC). There are other, non-ribosomal peptide biosynthesis (PEPTIDE BIOSYNTHESIS, NUCLEIC ACID-INDEPENDENT) mechanisms carried out by PEPTIDE SYNTHASES and PEPTIDYLTRANSFERASES. Further modifications of peptide chains yield functional peptide and protein molecules.	Biosynthesis, Peptide
D010944	Plants	Multicellular, eukaryotic life forms of kingdom Plantae. Plants acquired chloroplasts by direct endosymbiosis of CYANOBACTERIA. They are characterized by a mainly photosynthetic mode of nutrition; essentially unlimited growth at localized regions of cell divisions (MERISTEMS); cellulose within cells providing rigidity; the absence of organs of locomotion; absence of nervous and sensory systems; and an alternation of haploid and diploid generations. It is a non-taxonomical term most often referring to LAND PLANTS. In broad sense it includes RHODOPHYTA and GLAUCOPHYTA along with VIRIDIPLANTAE.	Plant
D002474	Cell-Free System	A fractionated cell extract that maintains a biological function. A subcellular fraction isolated by ultracentrifugation or other separation techniques must first be isolated so that a process can be studied free from all of the complex side reactions that occur in a cell. The cell-free system is therefore widely used in cell biology. (From Alberts et al., Molecular Biology of the Cell, 2d ed, p166)	Cellfree System,Cell Free System,Cell-Free Systems,Cellfree Systems,System, Cell-Free,System, Cellfree,Systems, Cell-Free,Systems, Cellfree
D005260	Female		Females
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia