Biomaterial Database

RNA/protein interactions in the 5'-untranslated leader of HSP70 mRNA in Drosophila lysates. Lack of evidence for specific protein binding. 1994

M A Hess, and R F Duncan

Department of Molecular Pharmacology/Toxicology, School of Pharmacy, University of Southern California, Los Angeles 90033.

We have investigated the hypothesis that preferential translation of the heat stress mRNAs requires the binding of a trans-acting protein factor. 32P-Labeled RNA probes covering the 5'-untranslated region (5'-UTR) of HSP70 mRNA were synthesized, and gel retardation and UV cross-linking assays performed to identify trans-acting sequence-specific RNA-binding factors. The results indicate that no HSP70 5'-UTR RNA-specific binding proteins exist. Reducing the "stringency" in the gel retardation binding analyses revealed several non-sequence-specific RNA-binding complexes. The proteins bind RNA more strongly than DNA, show minor preferences for specific sequences, but none binds more strongly to the HSP70 5'-UTR than to other non-heat stress RNAs. Ultraviolet cross-linking analysis identifies two principal HSP70 5'-UTR binding proteins, of approximately 50 and 70 kDa. The p50 binding activity is increased severalfold for all mRNAs in heat-stressed lysates, and its binding produces the primary gel-retarded complex. Further detailed analyses were performed to probe for any possible heat-influenced changes. RNA/protein interactions are not affected by capping. Neither the kinetics nor the salt sensitivity of protein binding is affected by heat. Binding analyses using partial or complete HSP70 5'-UTR give qualitatively similar conclusions. Binding analyses were also carried out with several "normal" 5'-UTRs to investigate whether a heat-induced repressor might be activated by heating. No normal mRNA-specific heat-induced binding changes are detected. We conclude that heat-induced alterations in RNA-binding proteins do not mediate preferential translation of heat stress mRNAs or repression of normal mRNAs.

UI	MeSH Term	Description	Entries
D007438	Introns	Sequences of DNA in the genes that are located between the EXONS. They are transcribed along with the exons but are removed from the primary gene transcript by RNA SPLICING to leave mature RNA. Some introns code for separate genes.	Intervening Sequences,Sequences, Intervening,Intervening Sequence,Intron,Sequence, Intervening
D008969	Molecular Sequence Data	Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.	Sequence Data, Molecular,Molecular Sequencing Data,Data, Molecular Sequence,Data, Molecular Sequencing,Sequencing Data, Molecular
D011485	Protein Binding	The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.	Plasma Protein Binding Capacity,Binding, Protein
D012097	Repressor Proteins	Proteins which maintain the transcriptional quiescence of specific GENES or OPERONS. Classical repressor proteins are DNA-binding proteins that are normally bound to the OPERATOR REGION of an operon, or the ENHANCER SEQUENCES of a gene until a signal occurs that causes their release.	Repressor Molecules,Transcriptional Silencing Factors,Proteins, Repressor,Silencing Factors, Transcriptional
D002478	Cells, Cultured	Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.	Cultured Cells,Cell, Cultured,Cultured Cell
D004330	Drosophila	A genus of small, two-winged flies containing approximately 900 described species. These organisms are the most extensively studied of all genera from the standpoint of genetics and cytology.	Fruit Fly, Drosophila,Drosophila Fruit Flies,Drosophila Fruit Fly,Drosophilas,Flies, Drosophila Fruit,Fly, Drosophila Fruit,Fruit Flies, Drosophila
D006360	Heat-Shock Proteins	Proteins which are synthesized in eukaryotic organisms and bacteria in response to hyperthermia and other environmental stresses. They increase thermal tolerance and perform functions essential to cell survival under these conditions.	Stress Protein,Stress Proteins,Heat-Shock Protein,Heat Shock Protein,Heat Shock Proteins,Protein, Stress
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
D001483	Base Sequence	The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.	DNA Sequence,Nucleotide Sequence,RNA Sequence,DNA Sequences,Base Sequences,Nucleotide Sequences,RNA Sequences,Sequence, Base,Sequence, DNA,Sequence, Nucleotide,Sequence, RNA,Sequences, Base,Sequences, DNA,Sequences, Nucleotide,Sequences, RNA
D012313	RNA	A polynucleotide consisting essentially of chains with a repeating backbone of phosphate and ribose units to which nitrogenous bases are attached. RNA is unique among biological macromolecules in that it can encode genetic information, serve as an abundant structural component of cells, and also possesses catalytic activity. (Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)	RNA, Non-Polyadenylated,Ribonucleic Acid,Gene Products, RNA,Non-Polyadenylated RNA,Acid, Ribonucleic,Non Polyadenylated RNA,RNA Gene Products,RNA, Non Polyadenylated