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Y Emori

Publications and source records attributed to Y Emori.

136 records · Page 8Linked to original sources
PubMed1982

Virion-associated RNA polymerase of bacteriophage phi 6 synthesizes three complete transcripts of double-stranded RNA genome in vitro.

Three single-stranded RNA transcripts synthesized in vitro by a virion-associated RNA polymerase of bacteriophage phi 6 were sequenced at their 5'- and 3'-termini. The sequences agreed with those of the + strands of the 3 double-stranded RNA segments [FEBS Lett. (1982) 141,111-115]. The results show that the transcription by phi 6 RNA polymerase initiates exactly at the 3'-ends of the template RNAs (-strands of the genomic RNA) and terminates exactly at the 5'-ends.

Coliphages↗
PubMed1981

A lytic enzyme in the bacteriophage phi 6 virion.

The results of our biochemical studies on the early step of phi 6 infection were schematically summarized in Fig. 6. To our knowledge, no other bacteriophage was reported to synthesize its mRNA in the parental subviral particle. The unique feature of the life cycle of this phage seems to be supported by two enzymes associated with the virion; the lytic enzyme and the RNA polymerase. The study of the RNA polymerase reaction observed in vitro showed the mode of the phi 6 RNA synthesis clearly and seems to be very useful to know the mechanism of the initial viral RNA synthesis in vivo.

Bacteriolysis↗
PubMed1980

Assignment of viral proteins to the three double-stranded RNA segments of bacteriophage phi 6 genome: translation of phi 6 messenger RNAs transcribed in vitro.

Pseudomonas phaseolicola bacteriophage phi 6 has a double-stranded (ds) RNA genome in three segments (L, M, S) which can serve as templates for in vitro transcription by phi 6 nucleocapsid. Single-stranded (ss) RNA (l, m, s) synthesized in vitro functioned as messenger RNA of viral proteins in an Escherichia coli cell-free protein-synthesizing system. Each of the three ssRNA species was isolated in virtually pure form and translated, providing a means of determining the polypeptides encoded by each segment. From the analysis of polypeptide products by SDS-polyacrylamide gel electrophoresis, coding assignments of three dsRNA segments were established. The major structural proteins P8 and P9 were shown to be encoded by the S segment transcript (s). The membrane proteins P3, P6, and P10 are encoded by the M segment transcript (m). The nucleocapsid proteins P1, P4, and P7 are probably synthesized by the L-segment transcript (l), but there remained a possibility that P4 and P7 are encoded also by the M-segment transcript (m). The nucleocapsid protein P2 was not synthesized in detectable amounts by transcripts of any segments in our experiments. This protein is known to be synthesized in small amounts in vivo. The lytic enzyme P5 could not be identified owing to the difficulty in separating P5 from products of the endogenous protein-synthesizing activity of E. coli extracts.

Bacteriophages↗
PubMed1980

Semi-conservative transcription of double-stranded RNA catalyzed by bacteriophage phi 6 RNA polymerase.

Treatment of Pseudomonas phaseolicola double-stranded RNA bacteriophage phi 6 with sodium deoxycholate converted the virions to nucleocapsids, which had in vitro RNA polymerase activity. The incorporation of [3H]UMP continued for at least 7 h. The initial incorporation was detected as intermediate RNA. Radioactivity was chased first into three segments of double-stranded RNA, and then into small, medium, and large species of single-stranded RNA successively via the intermediate RNA. Several copies of single-stranded RNA at least were synthesized from a template. The RNA synthesis clearly took place by a semi-conservative mechanism with respect to templates. That is, 5-bromo UTP was incorporated into one strand of double-stranded RNA to make a hybrid RNA of brominated and unbrominated strands. Furthermore, one strand of the 3H-labeled parental double-stranded RNA was shown to be released as single-stranded RNA.

Bacteriophages↗
PubMedDate not supplied

Evolutionary origin of a calcium-dependent protease by fusion of genes for a thiol protease and a calcium-binding protein?

Calcium-dependent protease (calcium protease) is apparently involved in a variety of cellular processes. Here we have attempted to clarify the role and regulatory mechanism of calcium protease by analysing its structure. The complete primary structure of calcium protease (relative molecular mass (Mr) 80,000 (80K), 705 amino acids) was deduced from the nucleotide sequence of cloned complementary DNA. The protein contains four distinct domains, and we have observed a marked similarity between the second and fourth domains and the papain-like thiol proteases and calmodulin-like calcium-binding proteins, respectively. This finding suggests that calcium protease arose from the fusion of genes for proteins of completely different function and evolutionary origin. Further, it provides functional insight into cellular regulatory mechanisms mediated by Ca2+ through calcium-binding proteins.

Amino Acid Sequence↗
PubMedDate not supplied

The nucleotide sequences of copia and copia-related RNA in Drosophila virus-like particles.

We have shown previously that Drosophila cells contain virus-like particles (VLPs) containing 5-kilobase (kb) RNA that hybridizes to a transposable element, termed copia. We have suggested that VLPs and copia are derivatives of viral particles and proviral forms, respectively, of 'copia' retrovirus, a putative Drosophila retrovirus. To further clarify the relationship between copia and copia-related RNA in VLPs (VLP H-RNA), we determined and compared their nucleotide sequences. VLP H-RNA was found to be an unspliced, genome-sized transcript of copia, and, like retroviral genome RNA, VLP H-RNA is terminally redundant with termini localized in the long terminal repeats (LTRs) of copia. VLP H-RNA contains two long open reading frames (ORFs), one of which includes the coding sequence for a predominant VLP protein of relative molecular mass (Mr) 31,000 (31K). Here we show that, in contrast to 17.6 ORF2, ORFs of copia have no extensive amino-acid sequence homology to the RT region of the reverse transcriptase of retrovirus in vertebrates. Because of a one-base insertion/deletion, the two ORFs in VLP H-RNA are fused and become a single, longer ORF in a genomic copia.

Amino Acid Sequence↗