Molecular cloning and analysis of an eIF-4A-related rat liver nuclear protein

• Published in: The Journal of biological chemistry Vol. 267; no. 18; pp. 12928 - 12935
• Main Authors: NAIR, S, DEY, R, SANFORD, J. P, DOYLE, D
• Format: Journal Article
• Language: English
• Published: Bethesda, MD American Society for Biochemistry and Molecular Biology 25-06-1992
• Subjects: Amino Acid Sequence; Analytical, structural and metabolic biochemistry; Animals; Base Sequence; Biological and medical sciences; Blotting, Northern; Blotting, Western; cDNA; Cell Cycle; Cloning, Molecular; DEAD-box RNA Helicases; DNA; Eukaryotic Initiation Factor-4A; Female; Fluorescent Antibody Technique; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation; genes; Holoproteins; initiation factor eIF-4A; liver; Liver - growth & development; Liver - metabolism; Molecular Sequence Data; Nuclear proteins; Nuclear Proteins - genetics; Nuclear Proteins - isolation & purification; nuclei; nucleotide sequence; Peptide Initiation Factors - genetics; predictions; Pregnancy; Protein Biosynthesis; Proteins; Rats; Restriction Mapping; Sequence Alignment; Vertebrata; Initiation factor eIF4A; Mammalia; Complementary DNA; Hepatocyte; Rat; Rodentia; Primary structure; Molecular cloning; Gene expression; Nuclear protein
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/S0021-9258(18)42363-0

In this paper, we report the cloning and analysis of a cDNA encoding a protein of M(r) congruent to 47,000 (p47), which is
localized to the nucleus of rat hepatocytes. The cDNA showed 37% overall sequence identity with a mouse translation initiation
factor, eIF-4A, which belongs to a family of putative ATP-dependent RNA helicases. We raised polyclonal antibodies against
the fusion protein and by indirect immunofluorescence on primary cultures of hepatocytes have demonstrated that p47 is located
in the nucleus. Although only approximately 27% of hepatocytes showed this nuclear staining, most of the nuclei in proliferating
transformed cell lines such as 3T3, PtK-1, and Hela were fluorescently labeled. Studies on serum-starved cells in culture
indicated that p47 was expressed in a cell cycle-dependent manner. Northern analyses demonstrated that the levels of p47 mRNA
were high in fetal liver and dropped significantly after birth to low levels in adult liver. Our data suggest that p47 is
developmentally regulated in rat liver at the mRNA level.