Can we redesign the normal msDNA pathway to produce new segments of DNA of our choosing?
Yes, for msDNA synthesis, an internal region of msDNA can be replaced with other sequences. msDNA can be used as a vector for in vivo production of an oligo of a specific sequence. (1,2) Mao and colleagues first demonstrated this by modifying the upper stem region of an E. coli msDNA molecule to produce an antisense DNA. Here is the paper. msDNA can also be successfully produced in eukaryotes such as yeast, and in a cell-free system consisting of purified reverse transcriptase and their cognate transcript.
Earlier, Lampson describes the Ec67-msDNA-retron has previously been cloned into a plasmid vector. The recombinant plasmid (pCl-1EP5b) contains the retron genes msr, msd, and the RT-ORF. This 5-kb region appears to supply all the information necessary to produce msDNA in E. coli K-12, the most common strain (3,4).
(2) Shimada, M., Inouye S., Inouye M. (1994). Requirements of the secondary structures in the primary transcript for multicopy single-standed DNA synthesis by reverse transcriptase from bacterial retron-Ec107. J. Biol. Chem.
(3) Lampson, B.C, Inouye S, Inouye M. (1991). msDNA of bacteria. Prog. Nucleic Acid Res. Mol. Biol. 40: 1–24.
(4) Lampson BC, Viswanathan M, Inouye M, Inouye S. (1990). Reverse transcriptase from Escherichia coli exists as a complex with msDNA and is able to synthesize double-stranded DNA. J Biol. Chem. 15: 8490–6.
-- Olivia H. 15 May 2009 2:37 EDT.