Disease relevance of Lysogeny

• Cleavage of the cII protein of phage lambda by purified HflA protease: control of the switch between lysis and lysogeny [1].
• Inhibition of protein synthesis in Escherichia coli by amino acid starvation or chloramphenicol addition increases the frequency of lysogeny by lambda phage two- to fourfold [2].
• However when the same MudI phage is injected by a phage P22 virion, lysogeny is reduced in a recA or recB mutant host [3].
• Interaction of the Cro repressor with the lysis/lysogeny switch of the Lactobacillus casei temperate bacteriophage A2 [4].
• When a Salmonella typhimurium strain that overexpressed sigma54 was infected with these challenge phages, E sigma54 bound to the nifH promoter and repressed transcription of the ant gene as seen by the increased frequency of lysogeny [5].

High impact information on Lysogeny

• This may result from the deficiency of cII protein caused by its decreased stability, since cII product is required for establishment of lysogeny [6].
• Since the himA gene product is required also for lambda site-specific recombination, it appears that the himA gene regulates lambda lysogeny at several levels [7].
• Thus, oop RNA seems to have a dual role, either favouring the lytic cycle as a primer for the initiation of lambda DNA replication, or leading to the establishment of lysogeny when elongated into the imm transcript, which directs synthesis of the repressor [8].
• Here we show that truncated forms of the key regulator of Mu lysogeny, the repressor Repc, accumulate in the absence of SsrA [9].
• The Cro protein specified by bacteriophage lambda is a repressor essential for normal lytic growth of the virus, thus having a physiological role distinct from that of cI, the repressor that maintains lysogeny [10].

Chemical compound and disease context of Lysogeny

• Temperate bacteriophages and lysogeny in lactic acid bacteria [11].
• We exploited the ability of L. monocytogenes to grow at room temperature and isolated bacteriophages that were incapable of growth at 37 degrees C. Transductions at this temperature therefore eliminated transductant killing and lysogeny, as did inclusion of citrate and the use of a low multiplicity of infection [12].
• The influence of the O-antigen and the capsular polysaccharide on the establishment of PlCmts lysogeny in Klebsiella pneumoniae [13].

Biological context of Lysogeny

• This epigenetic switch from lysogeny to the lytic state occurs on activation of the host SOS system, which leads to specific cleavage of CI repressor [14].
• Establishment of lysogeny in bacteriophage 186. DNA binding and transcriptional activation by the CII protein [15].
• The nature of the base pair changes in mutant phage, selected by their inability to establish lysogeny, are consistent with this mechanism of CII action [15].
• Functional assignments could be made to 33 gene products, including structural proteins, lysis components, DNA packaging proteins, lysogeny control functions and replication proteins [16].
• Comparative genomics identified candidate lysogenic conversion genes (LCG) downstream of the lysis cassette and within the lysogeny module [17].

Anatomical context of Lysogeny

• The similarity of PagC and Ail to Lom leads us to hypothesize that Lom is a virulence protein and that bacteriophage gene transfer and lysogeny could have led to the development of proteins essential to survival within macrophages and eucaryotic cell invasion [18].

Associations of Lysogeny with chemical compounds

• Lysogeny is widespread in the lactic acid bacteria [11].
• DNase I footprinting and in vivo mutational analysis suggest that lysogeny is maintained by c-repressor occupancy of the O2 operator, which precludes RNA polymerase from binding to Pe [19].
• Chloramphenicol stimulation of lysogeny by lambda regulatory mutants [2].
• Observations on lysogeny in glutamic acid bacteria [20].
• On the other hand, although cyclic AMP is required for efficient lysogeny, it did not appear to influence the synthesis, stability, or activity of cII protein [21].

Gene context of Lysogeny

• These results indicate that the himA gene participates in the regulation of the promoter sites specific of the establishment of lysogeny: PE for cl synthesis and PI, for Int production [7].
• An initial limitation caused by host factors would be amplified by the action of the cII and cIII products, at high multiplicity only, and the resulting inhibition would be essential in the "choice" towards lysogeny [22].
• Activation of the weak PRM promoter by cI protein is an essential process in the establishment of lysogeny [23].
• The c4 repressors of the temperate bacteriophages P1 and P7 inhibit antirepressor synthesis and are essential for establishment and maintenance of lysogeny [24].
• Our results indicate that one of the repressors required for maintenance of lysogeny, the mnt gene product, may be partially responsible for this phenomenon [25].

Analytical, diagnostic and therapeutic context of Lysogeny

• Sequence alignment with the lysogeny module from the cos-site-containing S. thermophilus bacteriophage phiSfi21 revealed areas of high sequence conservation (e.g., over the int gene), interspersed with regions of low or no sequence similarity (e.g., over the cro gene) [26].

References