DNA-directed enzyme synthesis in vitro

Structure of a Bacillus subtilis bacteriophage SPO1 gene encoding RNA polymerase sigma factor

Gene 28 of Bacillus subtilis bacteriophage SPO1 codes for a regulatory protein, a sigma factor known as sigma gp28, that binds to the bacterial core RNA polymerase to direct the recognition of phage middle gene promoters. middle promoters exhibit distinctive and conserved nucleotide sequences in two regions centered about 10 and 35 base pairs upstream from the start point of mRNA synthesis. Here we report the cloning of gene 28 and its complete nucleotide sequence. We infer that sigma gp28 is a 25,707-dalton protein of 220 amino acids. Neither the nucleotide sequence of gene 28 nor the inferred amino acid sequence of sigma gp28 exhibits extensive homology to the gene or protein sequence of Escherichia coli sigma factor.

On the structure of the deo operon of Escherichia coli

A characterization of a specialized transducing lambda phage for the deo operon (lambdaddeo), and some composite colE1-deo plasmids is given in this paper. This includes localization of the RSmaI, RHind/III, RBamI, and REcoRI sensitive sites. The deo genes have been localized by construction of composite colE1-deo plasmids. Using the DNA fragments, obtained by digestion with REcoRI and RHindIII, respectively, as templates in an in vitro protein synthesizing system, it has been possible to give the direction of transcription and the exact location of the deo genes, relative to the endonuclease sites. Furthermore, the cytO,P and deoO,P regions have been mapped relative to the structural genes. Supercoiled co1E1-deo DNA has been used as template in the in vitro system; this DNA gives essentially the same results as the endonuclease-fragmented DNA. The use of the different types of templates is discussed.

Identification and characterization of the in vitro synthesized gene products of bacteriophage M13

Bacteriophage M13 replicative form (RF) DNA was used to direct coupled transcription and translation in cell-free extracts prepared from Escherichia coli. By using RF DNA, isolated from cells infected with appropriate amber mutants of this phage, it has been possible to identify the products of genes I through IV. By using the same methods no gene-product relationship could be demonstrated for genes VI and VII. Coupled in vitro protein synthesis studies on RF-III DNA, a linear double-stranded DNA molecule, obtained after cleavage of either RF-I or RF-II DNA with the restriction endonuclease R.Hin11 from Haemophilus influenzae, indicated that the cleavage site for this enzyme is located in gene II. The in vitro products of both gene III and gene VIII are about 30 and six amino acids longer, respectively, than their native counterparts present within the virion. These results suggest that the latter proteins arise in vivo by cleavage of precursor molecules. Coupled transcription and translation studies on a DNA fragment which only contained the genetic information coding for gene IV protein, obtained after cleavage of RF DNA with the restriction endonuclease R.Hap11 from Haemophilus aphirophilus, indicated that a large number of the in vitro synthesized polypeptides are the result of premature chain termination.