Mahek Sharan, Institute of Applied Medicines and Research, Ghaziabad
Recently, a group of researchers of Hiroshima University published their work in Frontiers of Microbiology. They discovered that few bacteria like E.coli can aid genetic transfer of the plasmid via genes to different species and taxonomic kingdoms like Fungi and Protista. They studied in detail the genetic hat trick which in the future could be responsible for different applications. This can function as a tool to introduce different required characters or to suppress harmful characters across the genetic hosts. In this study of IncP1 plasmid, the researchers have studied various genes but their functions are still left to be examined to know their relation to conjugation.
What are plasmids?
Plasmids are an extrachromosomal and small DNA molecule that is present within the cell, mainly prokaryotes. Unlike chromosomal DNA, plasmids are not present in the nucleus and can replicate independently. Their shape is mainly circular with genes that help in the survival of the organism with various advantages. One of the most common advantages served by plasmid is resistance against antibiotics. There are various artificial plasmids constructed to participate in the recombinant DNA technology method.
How do bacteria replicate and transfer genetic information?
Reproduction is a way of exchanging genetic information to evolve and adapt. Reproduction is of two types: Sexual and asexual. Bacteria perform horizontal gene transfer in four ways: Transformation, Transduction, Transfection, and Conjugation. Conjugation fulfills the criteria of reproduction and genetic transfer. Conjugation is a way of conjugal transfer where a bacterium can connect to pass DNA and protein to the other bacterium. In conjugal transfer, the plasmids are transferred from one bacterium to another.
What Researchers discovered at Hiroshima University?
E.coli is rod-shaped bacteria that can transfer its plasmid to Protista and fungi. IncP1 is a particular type of plasmid that is present in many bacteria. Its presence in a large range of hosts makes it available for transfer to even hosts beyond the taxonomic range. Researchers hypothesized that this unique ability of plasmid comes from the cultivation of plasmid from different donors and hosts.
Kazuki Moriguchi, an associate professor of Graduate School of Integrated Sciences for life at Hiroshima University, commented on this research. He said, “Although conjugation factors encoded on plasmids have been extensively analyzed, those on the donor chromosome have not”. Researchers in this study surveyed genome-wide analysis on the collection of mutants of bacteria as donors to yeast. The “knocked out” genes were engineered for the mutants to study the performance of the overall system of a function of a gene. Knocking out a gene helps to study the function as the absence of that particular gene will show the absence of a particular function, enabling the study of gene function.
The results obtained:
Three mutants among 3,884 conjugates showed the transfer from E.coli to yeast or across other species with no accumulation of genetic material. The genes were analyzed but couldn’t be elucidated. Thus, the analysis only showed how genes appear to work. Out of these three genes, two repress the target which is still unknown in E.coli donors with inactivating the third gene that allows the unknown target to promote its activity. The results indicated that the complex of these three genes either repress or activate the conjugation or the IncP1 conjugation by either directly or indirectly following the same pathway of the IncP1 conjugation machinery.
Further, Professor Moriguchi added about the study, “We focused on ‘up’ mutants that can accelerate the conjugative transfer to both prokaryotes and eukaryotes as they could be potent donor strains applicable to gene introduction tools”.
Significance of the study:
The data of the research study help to facilitate the donor strains breeding from different bacteria, each with high affinity with the target organism. IncP1 ability of genetic transfer across the kingdoms could be the future of recombinant DNA technology to introduce different functions along with deletion of unwanted functions from the organisms, like the bacteria react to environmental changes.
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References:
- Zoolkefli, F. I. R. M., Moriguchi, K., Cho, Y., Kiyokawa, K., Yamamoto, S., & Suzuki, K. (2021). Isolation and analysis of donor chromosomal genes whose deficiency is responsible for accelerating bacterial and trans-kingdom conjugations by incp1 t4ss machinery. Frontiers in Microbiology, 12, 620535. https://doi.org/10.3389/fmicb.2021.620535
Very informative Mahek,
Great research I must say – All aspects of Mutant Genes taking into consideration.
Also the usage of diagrams for illustrations are perfectly aligned with the Topic.
Great Research Mahek Sharan
Regards
Amitabh