Well I was torn about this. Should I title the post ” ICE, ICE, Bacterial BABIES” or say something about sex? I settled on sex, but not sure if that was wise.
Anyway – quick post to say that there are two papers from PLoS Genetics last month that caught my eye. They are
- PLoS Genetics: The Repertoire of ICE in Prokaryotes Underscores the Unity, Diversity, and Ubiquity of Conjugation. Guglielmini J, Quintais L, Garcillán-Barcia MP, de la Cruz F, Rocha EPC (2011) PLoS Genet 7(8): e1002222. doi:10.1371/journal.pgen.1002222
- PLoS Genetics: A Broad Brush, Global Overview of Bacterial Sexuality Achtman M (2011) PLoS Genet 7(8): e1002255. doi:10.1371/journal.pgen.1002255
The latter is a “review” paper linked to the first one which is a research paper. The papers together provide both a good background and a window into modern studies of “ICEs” or integrative conjugative elements in bacteria.
I like the summary from the first paper:
Some mobile genetic elements spread genetic information horizontally between prokaryotes by conjugation, a mechanism by which DNA is transferred directly from one cell to the other. Among the processes allowing genetic transfer between cells, conjugation is the one allowing the simultaneous transfer of larger amounts of DNA and between the least related cells. As such, conjugative systems are key players in horizontal transfer, including the transfer of antibiotic resistance to and between many human pathogens. Conjugative systems are encoded both in plasmids and in chromosomes. The latter are called Integrative Conjugative Elements (ICE); and their number, identity, and mechanism of conjugation were poorly known. We have developed an approach to identify and characterize these elements and found more ICEs than conjugative plasmids in genomes. While both ICEs and plasmids use similar conjugative systems, there are remarkable preferences for some systems in some elements. Our evolutionary analysis shows that plasmid conjugative systems have often given rise to ICEs and vice versa. Therefore, ICEs and conjugative plasmids should be regarded as one and the same, the differences in their means of existence in cells probably the result of different requirements for stabilization and/or transmissibility of the genetic information they contain.
That should be enough to get people started. And that is alas all I have time to write about here.