Structure of the Abelson murine leukemia virus genome and the homologous cellular gene: Studies with cloned viral DNA

A bacteriophage lambda vector for cloning large DNA fragments made with several restriction enzymes

Construction of coliphage lambda Charon vectors with BamHI cloning sites.

https://www.seas.upenn.edu/%7Epurohit/mypapers/myvirol.pdf

The effect of genome length on ejection forces in bacteriophage lambda.

A series of deletions, Mu insertions and point mutations affecting the malK-lamB operon have been isolated. They were used to establish a deletion map of this operon, which could be divided in 27 intervals, with 16 in malK and 11 in lamB. One interesting feature of this map is the lack of randomness in the distribution of Mu insertions in the lamB gene; by using data published elsewhere on the physical length of the deletion intervals it can be concluded that about 25% of these Mu insertions are clustered in a segment representing 3% of the gene, and another 20% in a segment representing 2 to 8% of the gene. This map is presently being used to study the biosynthesis, structure, and function of the lamB product, which is an outer membrane protein involved in the transport of maltose and maltodextrin, and which in addition constitutes the receptor for phage λ.

Structure of the malB region in Escherichia coli K12

Gene duplication followed by independent evolution of the duplicated genes appears to be a basic feature of the genetics of higher organisms (see Bryson and Vogel, 1965). Such duplications are rare in Escherichia coli as judged by measurements of repeating DNA sequences (Britten and Kohne, 1968), although there are multiple copies of the ribosomal RNA genes in E. coli (Yankofsky and Spiegelman, 1962; Moore and McCarthy, 1967). There have been few studies of tandem duplications in phages. Duplications in the T4 r II region have been obtained by a strong selection technique (Weil et al., 1965; Parma and Ingraham, 1970). We have found that many of the spontaneous “revertants” of the deletion mutant t del 33 (Franklin, 1967) are duplication mutants, with changes at different locations on the phage chromosome. This phage has many advantages for studying the properties and mechanism of formation of duplication mutants. Some advantages which we have exploited in the present work are as follows. (1) Since the base sequence in 80- λ hy 1 DNA is nonpermuted and the phage chromosome can be extracted as a DNA molecule of definite length, a duplication mutant can be identified as such and the end points of the duplicated segment can be located by electron microscopy of DNA heteroduplexes. (2) The dependence of phage buoyant density on DNA length provides a nonspecific selection method for mutants which have longer DNA molecules. (Selection by plaque morphology is also possible in many cases.) (3) An independent method of identifying duplication mutants is based...

A. J. D. Bellett

Papers

Tandem Genetic Duplications in a Derivative of Phage Lambda