Nav: Home

Mechanism of successful horizontal gene transfer between divergent organisms explained

December 20, 2016

Tsukuba, Japan - The transfer of genes from one organism to another is potentially a rapid way for evolution to occur and for complicated novel functions to emerge. However, even when the two organisms in question are in close proximity to each other, such as in a symbiotic or parasitic relationship, the transfer of genetic material and its introduction into a new genome only marks the initial step for successful horizontal gene transfer. It is also necessary for the gene to be expressed in a way that benefits the new host and ensures that it is passed down through the generations.

In a new discovery that increases our understanding of gene transfer, a research team centered at University of Tsukuba has studied a gene in marine invertebrates called ascidians originally came from a common bacterium. The team has revealed the likely mechanism by which this gene ended up being expressed in a functionally important and tissue-specific way.

The team focused on marine filter feeders called ascidians and their cellulose synthase gene. This gene encodes a protein that helps form an external protective coating, the loss of which leads to a lack of cellulose production and has adverse effects on these organisms. This gene is specifically expressed in the protective outer layer of cells called the epidermis, which was suggested to be key to its coating-related function.

"We showed that a region adjacent to the cellulose synthase gene is responsible for its specific epidermal expression," study coauthor Yosuke Ogura says. "Sequence analysis revealed that this region contains a binding site of a transcription factor called AP-2 and, when we induced mutations in this binding site, the expression of cellulose synthase in the ascidian epidermis disappeared."

Although all DNA sequences consists of the four letters or bases of A, C, G, and T, their proportions differ depending on the organism. For example, in actinobacteria , over 70% of the DNA consists of Gs and Cs, while the genome of ascidians has an abundance of As and Ts. The AP-2 binding site in ascidians is actually GC-rich, suggesting it originated from another species. It turns out that this GC bias may have been key to its functional integration.

"AP-2 inherently binds to GC-rich regions, so it was already primed to start interacting with the bacterial GC-rich DNA once it had integrated into the ascidian genome," first author Yasunori Sasakura says. "The GC-specificity and epidermal expression of AP-2 meant that the introduced cellulose synthase gene could immediately be expressed in its new surroundings in a beneficial way."

These findings provide interesting insight into one way in which the conditions in the new host can facilitate expression of a newly transferred gene and its integration into the host's functions, reducing the improbability that a randomly inserted foreign gene could actually be beneficial.
-end-
The article "Transcriptional regulation of a horizontally transferred gene from bacterium to chordate" was published in Proceedings of the Royal Society of London B at http://dx.doi.org/10.1098/rspb.2016.1712

University of Tsukuba

Related Genome Articles:

Breakthrough in genome visualization
Kadir Dede and Dr. Enno Ohlebusch at Ulm University in Germany have devised a method for constructing pan-genome subgraphs at different granularities without having to wait hours and days on end for the software to process the entire genome.
Sturgeon genome sequenced
Sturgeons lived on earth already 300 million years ago and yet their external appearance seems to have undergone very little change.
A sea monster's genome
The giant squid is an elusive giant, but its secrets are about to be revealed.
Deciphering the walnut genome
New research could provide a major boost to the state's growing $1.6 billion walnut industry by making it easier to breed walnut trees better equipped to combat the soil-borne pathogens that now plague many of California's 4,800 growers.
Illuminating the genome
Development of a new molecular visualisation method, RNA-guided endonuclease -- in situ labelling (RGEN-ISL) for the CRISPR/Cas9-mediated labelling of genomic sequences in nuclei and chromosomes.
A genome under influence
References form the basis of our comprehension of the world: they enable us to measure the height of our children or the efficiency of a drug.
How a virus destabilizes the genome
New insights into how Kaposi's sarcoma-associated herpesvirus (KSHV) induces genome instability and promotes cell proliferation could lead to the development of novel antiviral therapies for KSHV-associated cancers, according to a study published Sept.
Better genome editing
Reich Group researchers develop a more efficient and precise method of in-cell genome editing.
Unlocking the genome
A team led by Prof. Stein Aerts (VIB-KU Leuven) uncovers how access to relevant DNA regions is orchestrated in epithelial cells.
Why do we need one pair of genome?
Scientists have unraveled how the cell replication process destabilizes when it has more, or less, than a pair of chromosome sets, each of which is called a genome -- a major step toward understanding chromosome instability in cancer cells.
More Genome News and Genome Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: Reinvention
Change is hard, but it's also an opportunity to discover and reimagine what you thought you knew. From our economy, to music, to even ourselves–this hour TED speakers explore the power of reinvention. Guests include OK Go lead singer Damian Kulash Jr., former college gymnastics coach Valorie Kondos Field, Stockton Mayor Michael Tubbs, and entrepreneur Nick Hanauer.
Now Playing: Science for the People

#562 Superbug to Bedside
By now we're all good and scared about antibiotic resistance, one of the many things coming to get us all. But there's good news, sort of. News antibiotics are coming out! How do they get tested? What does that kind of a trial look like and how does it happen? Host Bethany Brookeshire talks with Matt McCarthy, author of "Superbugs: The Race to Stop an Epidemic", about the ins and outs of testing a new antibiotic in the hospital.
Now Playing: Radiolab

Dispatch 6: Strange Times
Covid has disrupted the most basic routines of our days and nights. But in the middle of a conversation about how to fight the virus, we find a place impervious to the stalled plans and frenetic demands of the outside world. It's a very different kind of front line, where urgent work means moving slow, and time is marked out in tiny pre-planned steps. Then, on a walk through the woods, we consider how the tempo of our lives affects our minds and discover how the beats of biology shape our bodies. This episode was produced with help from Molly Webster and Tracie Hunte. Support Radiolab today at Radiolab.org/donate.