Messenger RNAs (mRNAs), the intermediates of gene expression which direct protein synthesis, are found in eukaryotic cells associated with a specific subset of cytoplasmic proteins. The mRNA-protein complexes, termed mRNP particles (mRNPs), are distinct structural entitles different in protein composition, structure, function and subcellular compartmentalization from nuclear pre-mRNA-protein (hnRNP) particles. A plethora of recent observations indicate that mRNP proteins play a cardinal role in mRNA transport, translation, stability and localization. The mRNP proteins can be photochemically crosslinked to the mRNA in intact cells and the crosslinked complexes can be readily isolated. We have studied these complexes in normal and virus-infected cells across eukaryotes. In all of these, the most abundant protein is a 72,000 dalton protein which is crosslinked to the poly(A) tail of the mRNA. The poly(A) binding protein is a highly conserved, poorly immunogenic protein that has been the focus of much interest because it appears to play a key role in mRNA metabolism. We have immunized mice with crosslinked purified mRNP complexes to produce antibodies to the mRNP proteins. Antibodies were obtained to the poly(A) binding protein from yeast, and we have begun to characterize the protein and have isolated the gene encoding it. The antibodies and the gene are the first probes for this protein from any organism and they open the way of its molecular and genetic characterization. We shall investigate the structure, function, properties and localization of the mRNP proteins and the mRNP complexes with particular emphasis on the poly(A) binding protein. Additional antibodies to mRNP proteins will be produced. The cDNAs encoding these proteins will be isolated by immunological screening of expression vector libraries. The complete amino acid sequence of the proteins will be determined by nucleotide sequencing of the cDNAs, and their mRNAs and genes will be characterized. The interaction of the proteins with RNA will be studied in detail. The subcellular localization of the proteins will be examined by immunocytochemical techniques. The functions of the proteins will be investigated in vivo by gene disruption and mutagenesis in yeast and by introduction of antibodies into living animal cells, and in vitro using cell free systems for protein synthesis and mRNA transcription, splicing and polyadenylation. From these studies a better picture of ho mRNA is formed, maintained and functions in animal cells is likely to emerge.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM031888-05
Application #
3280295
Study Section
Molecular Biology Study Section (MBY)
Project Start
1983-12-01
Project End
1991-11-30
Budget Start
1987-12-01
Budget End
1988-11-30
Support Year
5
Fiscal Year
1988
Total Cost
Indirect Cost
Name
Northwestern University at Chicago
Department
Type
Schools of Arts and Sciences
DUNS #
City
Evanston
State
IL
Country
United States
Zip Code
60208
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Dreyfuss, G; Choi, Y D; Adam, S A (1989) The ribonucleoprotein structures along the pathway of mRNA formation. Endocr Res 15:441-74
Swanson, M S; Dreyfuss, G (1988) Classification and purification of proteins of heterogeneous nuclear ribonucleoprotein particles by RNA-binding specificities. Mol Cell Biol 8:2237-41
Pinol-Roma, S; Choi, Y D; Matunis, M J et al. (1988) Immunopurification of heterogeneous nuclear ribonucleoprotein particles reveals an assortment of RNA-binding proteins. Genes Dev 2:215-27
Dreyfuss, G; Swanson, M S; Pinol-Roma, S (1988) Heterogeneous nuclear ribonucleoprotein particles and the pathway of mRNA formation. Trends Biochem Sci 13:86-91
Swanson, M S; Dreyfuss, G (1988) RNA binding specificity of hnRNP proteins: a subset bind to the 3' end of introns. EMBO J 7:3519-29
Swanson, M S; Nakagawa, T Y; LeVan, K et al. (1987) Primary structure of human nuclear ribonucleoprotein particle C proteins: conservation of sequence and domain structures in heterogeneous nuclear RNA, mRNA, and pre-rRNA-binding proteins. Mol Cell Biol 7:1731-9
Adam, S A; Dreyfuss, G (1987) Adenovirus proteins associated with mRNA and hnRNA in infected HeLa cells. J Virol 61:3276-83
Adam, S A; Choi, Y D; Dreyfuss, G (1986) Interaction of mRNA with proteins in vesicular stomatitis virus-infected cells. J Virol 57:614-22
Adam, S A; Nakagawa, T; Swanson, M S et al. (1986) mRNA polyadenylate-binding protein: gene isolation and sequencing and identification of a ribonucleoprotein consensus sequence. Mol Cell Biol 6:2932-43

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