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Functional adaptation of tRNAs to protein biosynthesis in a highly differentiated cell system. III. Induction of isoacceptor tRNAs during the secretion of fibroin in the silkgland of Bombyx mori L.
Author(s) -
Garel J.P.,
Mandel P.
Publication year - 1971
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(71)80189-8
Subject(s) - fibroin , bombyx mori , citation , transfer rna , genetics , biology , combinatorics , rna , library science , computer science , gene , mathematics , silk , telecommunications
We have previously demonstrated that, in a differentiated cell system, a linear correlation exists between the amino acid distribution of a major protein and the corresponding tRNAs, e.g. the crystallines in the internal cortical zone of the lens [l] and the secreted fibroin in the posterior part of the silkgland of the silkworm Bombyx mot-i L [2]. This regulation process also concerns the intracellular level of aminoacyl-tRNA ligases (EC.6.1 .l .) in the silkgland; their concentrations are almost proportional to the tRNA population during the secreted period [3]. For a better understanding of the regulation mechanism of protein biosynthesis at the translational level, tRNAs specific for the four major amino acids of the fibroin (Ala, Gly, Ser and Tyr) were individually subjected to a fractionation procedure. Chromatography on methylated albumin-kieselguhr (MAK) columns demonstrated qualitative differences among isoacceptor tRNAs, particularly for tRNA* and tRNAGb from the end of the cell growth period (4th day) to the secretion period (8th day) during the Vth instar of the silkworm. These qualitative differences correspond to a diffbential8 fold increase for the first isoacceptor tRNA compared with a 20-30 fold increase for the 2nd or/and the 3rd isoacceptor species. 2. Materials and methods