Changes in in vivo levels of charged transfer RNA species during development of the posterior silkgland of Bombyx mori

The turnover of tRNAs microinjected into animal cells

“…The methyl labeling procedure is not, however, without potential error. It can be seen in Figure 3 that the 3H-tRNA values for SV3T3 cells on day 4 were not used to construct the turnover curves. SV3T3 cells were not fed during those studies, and subsequent experiments showed that the rate of tRNA turnover in SV3T3 cells as measured by methyl labeling was sensitive Either SV3T3 cells (upper panels) or TC7 cells (lower panels) were labeled with 3H-methionine and microinjected with 32P-tRNA isolated from E. coli or TC7 cells.…”

Transfer RNA in posterior silk gland of Bombyx mori: polyacrylamide gel mapping of mature transfer RNA, identification and partial structural characterization of major isoacceptor species

“…The identification of tRNA spots and assessment of their purity was accomplished by parallel electrophoresis of purified isoacceptor tRNA species, coelectrophoresis of purified nonlabeled tRNA with unfractionated 32P-labeled tRNA, and fingerprint analysis of RNase T| digests of labeled tRNA spots. A few nonlabeled tRNA species were also eluted from gels and analyzed for amino acid acceptance (Delaney and Siddiqui, 1975). To aid in identification, marker nonlabeled tRNAA!a and tRNAG,y species were prepared by BD-cellulose column chromatography (Delaney and Siddiqui, 1975;Meza et al, 1977) and tRNASer and tRNA,yr were obtained by countercurrent distribution (Garel et al, 1976b;Hentzen et al, 1976).…”

“…A few nonlabeled tRNA species were also eluted from gels and analyzed for amino acid acceptance (Delaney and Siddiqui, 1975). To aid in identification, marker nonlabeled tRNAA!a and tRNAG,y species were prepared by BD-cellulose column chromatography (Delaney and Siddiqui, 1975;Meza et al, 1977) and tRNASer and tRNA,yr were obtained by countercurrent distribution (Garel et al, 1976b;Hentzen et al, 1976). Alanyl-tRN A from the posterior silk gland of 5-7 day old larvae separated on BD-cellulose into a minor (tRNAAlai) and a major (tRNAAla2) peak in a ratio of about 20:80, the latter eluting at a higher salt concentration.…”

“…In the following report, gel mapping of the posterior silk gland and carcass tRNA by two-dimensional polyacrylamide gel electrophoresis and characterization of the major posterior silk gland tRNA species by ribonuclease Ti oligonucleotide fingerprinting and by nucleotide composition analysis is described. The tRNA gel patterns reflect the highly characteristic quantitative and qualitative tRNA distributions of the B. mori tissues (Matsuzaki, 1966;Garel et al, 1970; Delaney and Siddiqui, 1975). The analysis can also be used for scanning the changes in accumulation of specific tRNA during growth and differentiation of the silk gland and other tissues.…”

“…et al, 1975). It was proposed (Garel, 1974(Garel, ,1976) that such an adaptation of tRNA population which results from quantitative changes in specific isoacceptor tRNA species (Garel et al, 1970;Delaney and Siddiqui, 1975;Araya et al, 1975) could ensure rapid and efficient decoding of fibroin mRNA. Silk fibroin is composed mainly of the four amino acids mentioned above and is synthesized exclusively in the posterior part of the silk gland (Tashiro et al, 1968;Daillie et al, 1971).…”