Non-polysomal poly(A)-containing messenger ribonucleoproteins of cryptobiotic gastrulae of Artemia salina
In: European Journal of Biochemistry. Springer: Berlin. ISSN 0014-2956; e-ISSN 1432-1033, more
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| Authors | | Top |
- Slegers, H.
- De Herdt, E.
- Kondo, M.
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| Abstract |
Non-polysomal poly(A)-containing messenger ribonucleoprotein (mRNP) of Artemia salina has been isolated by thermal chromatography on oligo(dT)-cellulose in moderate (250 mM) and low (50 mM NaCl and 5 mM MgCl2) ionic strength. The purified particles sedimented between 5 S and 30 S and banded at a density of 1.38–1.40 g/cm3 and 1.26–1.27 g/cm3 in CsCl and sucrose isopycnic centrifugation, respectively. The translatability of the mRNP in a cell-free system depended on the conditions of isolation. The protein composition of the free mRNP is independent of the conditions used in oligo(dT)-cellulose chromatography. The proteins have Mr of 87000, 76000, 65000, 50000, 45000, 38000 and 23500. A specific set of proteins is associated with different ribonucleoproteins, although some proteins are present on multiple particles. The main 17 ± 2-S particle is composed of proteins with Mr of 87000, 76000, 45000 and 38000. Approximately the same proteins were present on free mRNP and mRNP isolated from non-polysomal mRNP-ribosome complexes. Poly(A)-binding proteins have Mr of 38000 and 23500. The 38000-Mr protein comprised at least 60% of the total mRNP protein. Poly(A)-binding proteins with Mr of 38000 and 76000 are also present in a free state in the cytoplasm. A relation between the main poly(A)-binding mRNP protein and the helix-destabilizing protein HD40 [Marvil, D. K., Nowak, L., and Szer, W. (1980) J. Biol. Chem. 255, 6466–6472] is discussed. |
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