To study the effect of intron size on splicing efficiency we have varied the size of the avian leukosis virus (ALV) env mRNA intron in a cloned ALV genome. This was accomplished by deletion of ALV sequences or insertion of phage lambda DNA. The effect of these modifications on splicing was analyzed by microinjection of the modified clones into RSV(-) chicken cells. Viral env mRNA when transcrib...

The plaque assay is the traditional method for the quantification of bacteriophage, particularly for lambda cloning vectors. Unfortunately, this technique is fraught with procedural difficulties, and the quality of the data obtained from this "gold standard" assay may be inaccurate due to the subjective interpretation of the results. The application of quantitative real-time PCR (QPCR) technolo...

INTRODUCTION......... . ...... ................. .. ................. . .... . . ................. ......... 933 NOTIONS ABOUT RECOGNITION..... ................ . . .............. . . ..... . ......... . . ..... 934 THE HTH MOTIF... ..... ....... ................. .. . ................ .... . . .... ........... . .. . ..... .. 936 STRUCTURES.... . . . ..... .. ......... . . ................ ......

A robust selection system affording phage display of the DNA-binding helix-turn-helix protein Cro is presented. The aim of the work was to construct an experimental system allowing for the construction and isolation of Cro-derived protein with new DNA-binding properties. A derivative of the phage lambda Cro repressor, scCro8, in which the protein subunits had been covalently connected via a pep...

HE chromosome of temperate bacteriophage lambda consists of three functionally distinct regions of approximately equal size. The right arm contains the genes for regulation (EISEN et al. 1966), DNA synthesis (JOYNER et al. 1966) and cell lysis (HARRIS (et al. 1967). The central portion of the h DNA molecule is concerned with the processes of prophage integration (KELLENBERGER, ZICHICHI and WEIG...

Nonreplicating lambda phage DNA in homoimmune Escherichia coli lysogens provides a useful model system for study of processes that activate DNA for homologous recombination. We measured recombination by extracting phage DNA from infected cells, using it to transfect recA recipient cells, and scoring the frequency of recombinant infective centers. With unirradiated phage, recombinant frequencies...

Genomic libraries from Streptococcus mutans OMZ175 were constructed in bacteriophage vectors. DNA fragments 1 to 2 kilobases in length were cloned in expression vector lambda gt11. S. mutans DNA fragments 15 to 20 kilobases in length were inserted in the BamHI site of phage EMBL3. Rabbit antiserum raised against an S. mutans saliva-interacting protein with a molecular weight of 74,000, designat...

The immunochemical properties of type 5 M protein antigens that were expressed in Escherichia coli K-12 by recombinant lambda bacteriophages isolated from a gene bank of serotype 5 Streptococcus pyogenes have been analyzed in detail. M proteins from partially purified bacteriophage lysates displayed precipitin lines of identity with a purified peptic extract of type 5 M protein (pep M5) in immu...

Most cells of a given species contain essentially the same complement of genes, yet individual genetically identical cells can assume dramatically different appearances and behaviours. This is achieved largely by the regulation of the transcription of individual genes, orchestrated by the specific binding of proteins to nearby sites in the genome—a principle first recognised 50 years ago by Fra...

The two species of covalently closed circular DNA molecules of bovine leukemia virus were cloned in the lambda phage vector lambda gtWES X lambda B. Of the nine independent recombinant lambda-bovine leukemia virus clones that were analyzed, three were derived from the small and six were derived from the large circular molecules carrying, respectively, one and two copies of the long terminal rep...