Abstract
The phage Mu mom gene controls an unusual DNA modification. Expression of the mom function requires an active host (dam+) DNA adenine methylase [S-adenosyl-L-methionine:DNA (6-aminopurine)-methyltransferase]; in dam- hosts, Mu development is normal except that the viral DNA does not undergo the mom modification. The present communication compares transcription of the mom gene in dam+ versus dam- cells. 32P-labeled probes were prepared by nick-translation of a purified mom gene-containing restriction fragment and of virion DNA, respectively. These probes were hybridized with various RNAs blotted onto nitrocellulose filters (after fractionation by agarose gel electrophoresis). The salient findings are: (i) mom-specific RNA was readily detected in dam+ lysogenic cells, but only after induction of the Mu prophage; (ii) the level of mom RNA was decreased at least to 1/20th in induced dam- Mu lysogens; and (iii) little difference, if any, was observed between dam+ and dam- cells with respect to total Mu transcripts produced after prophage induction. These results are in accord with the known pattern of mom gene expression and Mu development. They show that the host (dam+) DNA adenine methylase activity is required for transcription of the mom gene. This represents a unique example where a DNA methylase exerts a positive regulatory role in mRNA transcription; alternative mechanisms for this process will be discussed.
Full text
PDF



Images in this article
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Allet B., Bukhari A. I. Analysis of bacteriophage mu and lambda-mu hybrid DNAs by specific endonucleases. J Mol Biol. 1975 Mar 15;92(4):529–540. doi: 10.1016/0022-2836(75)90307-1. [DOI] [PubMed] [Google Scholar]
- Bukhari A. I., Froshauer S., Botchan M. Ends of bacteriophage mu DNA. Nature. 1976 Dec 9;264(5586):580–583. doi: 10.1038/264580a0. [DOI] [PubMed] [Google Scholar]
- Bukhari A. I., Taylor A. L. Influence of insertions on packaging of host sequences covalently linked to bacteriophage Mu DNA. Proc Natl Acad Sci U S A. 1975 Nov;72(11):4399–4403. doi: 10.1073/pnas.72.11.4399. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Chaconas G., de Bruijn F. J., Casadaban M. J., Lupski J. R., Kwoh T. J., Harshey R. M., DuBow M. S., Bukhari A. I. In vitro and in vivo manipulations of bacteriophage Mu DNA: cloning of Mu ends and construction of mini-Mu's carrying selectable markers. Gene. 1981 Jan-Feb;13(1):37–46. doi: 10.1016/0378-1119(81)90041-x. [DOI] [PubMed] [Google Scholar]
- Chow L. T., Kahmann R., Kamp D. Electron microscopic characterization of DNAs of non-defective deletion mutants of bacteriophage Mu. J Mol Biol. 1977 Jul 15;113(4):591–609. doi: 10.1016/0022-2836(77)90224-8. [DOI] [PubMed] [Google Scholar]
- Clewell D. B., Helinski D. R. Supercoiled circular DNA-protein complex in Escherichia coli: purification and induced conversion to an opern circular DNA form. Proc Natl Acad Sci U S A. 1969 Apr;62(4):1159–1166. doi: 10.1073/pnas.62.4.1159. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Daniell E., Abelson J., Kim J. S., Davidson N. Heteroduplex structures of bacteriophage Mu DNA. Virology. 1973 Jan;51(1):237–239. doi: 10.1016/0042-6822(73)90385-1. [DOI] [PubMed] [Google Scholar]
- Daniell E., Kohne D. E., Abelson J. Characterization of the inhomogeneous DNA in virions of bacteriophage Mu by DNA reannealing kinetics. J Virol. 1975 Apr;15(4):739–743. doi: 10.1128/jvi.15.4.739-743.1975. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Denhardt D. T. A membrane-filter technique for the detection of complementary DNA. Biochem Biophys Res Commun. 1966 Jun 13;23(5):641–646. doi: 10.1016/0006-291x(66)90447-5. [DOI] [PubMed] [Google Scholar]
- Hattman S., Brooks J. E., Masurekar M. Sequence specificity of the P1 modification methylase (M.Eco P1) and the DNA methylase (M.Eco dam) controlled by the Escherichia coli dam gene. J Mol Biol. 1978 Dec 15;126(3):367–380. doi: 10.1016/0022-2836(78)90046-3. [DOI] [PubMed] [Google Scholar]
- Hattman S. Specificity of the bacteriophage Mu mom+ -controlled DNA modification. J Virol. 1980 Apr;34(1):277–279. doi: 10.1128/jvi.34.1.277-279.1980. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hattman S. Unusual modification of bacteriophage Mu DNA. J Virol. 1979 Nov;32(2):468–475. doi: 10.1128/jvi.32.2.468-475.1979. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Herman G. E., Modrich P. Escherichia coli dam methylase. Physical and catalytic properties of the homogeneous enzyme. J Biol Chem. 1982 Mar 10;257(5):2605–2612. [PubMed] [Google Scholar]
- Kamp D., Kahmann R., Zipser D., Broker T. R., Chow L. T. Inversion of the G DNA segment of phage Mu controls phage infectivity. Nature. 1978 Feb 9;271(5645):577–580. doi: 10.1038/271577a0. [DOI] [PubMed] [Google Scholar]
- Khatoon H., Bukhari A. I. Bacteriophage Mu-induced modification of DNA is dependent upon a host function. J Bacteriol. 1978 Oct;136(1):423–428. doi: 10.1128/jb.136.1.423-428.1978. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kwoh D. Y., Zipser D., Erdmann D. S. Genetic analysis of the cloned genome of phage Mu. Virology. 1980 Mar;101(2):419–431. doi: 10.1016/0042-6822(80)90455-9. [DOI] [PubMed] [Google Scholar]
- Lacks S., Greenberg B. Complementary specificity of restriction endonucleases of Diplococcus pneumoniae with respect to DNA methylation. J Mol Biol. 1977 Jul;114(1):153–168. doi: 10.1016/0022-2836(77)90289-3. [DOI] [PubMed] [Google Scholar]
- Langridge J., Langridge P., Bergquist P. L. Extraction of nucleic acids from agarose gels. Anal Biochem. 1980 Apr;103(2):264–271. doi: 10.1016/0003-2697(80)90266-3. [DOI] [PubMed] [Google Scholar]
- Marinus M. G., Morris N. R. Isolation of deoxyribonucleic acid methylase mutants of Escherichia coli K-12. J Bacteriol. 1973 Jun;114(3):1143–1150. doi: 10.1128/jb.114.3.1143-1150.1973. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Thomas P. S. Hybridization of denatured RNA and small DNA fragments transferred to nitrocellulose. Proc Natl Acad Sci U S A. 1980 Sep;77(9):5201–5205. doi: 10.1073/pnas.77.9.5201. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Toussaint A. DNA modification of bacteriophage Mu-1 requires both host and bacteriophage functions. J Virol. 1977 Sep;23(3):825–826. doi: 10.1128/jvi.23.3.825-826.1977. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Toussaint A., Desmet L., Faelen M. Mapping of the modification function of temperate phage Mu-1. Mol Gen Genet. 1980 Jan;177(2):351–353. doi: 10.1007/BF00267450. [DOI] [PubMed] [Google Scholar]
- Toussaint A. The DNA modification function of temperate phage Mu-1. Virology. 1976 Mar;70(1):17–27. doi: 10.1016/0042-6822(76)90232-4. [DOI] [PubMed] [Google Scholar]