Mostrando entradas con la etiqueta gene. Mostrar todas las entradas
Mostrando entradas con la etiqueta gene. Mostrar todas las entradas

viernes, 11 de diciembre de 2015

Scaling up synthetic-biology innovation

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Gen9's BioFab platform synthesizes small DNA fragments on silicon chips and uses other technologies to build longer DNA constructs from those fragments. Done in a parallel, this produces hundreds to thousands of DNA constructs simultaneously. Shown here is an automated liquid-handling instrument that dispenses DNA onto the chips. Courtesy of Gen9
MIT professor’s startup makes synthesizing genes many times more cost effective.
Inside and outside of the classroom, MIT professor Joseph Jacobson has become a prominent figure in — and advocate for — the emerging field of synthetic biology.

As head of the Molecular Machines group at the MIT Media Lab, Jacobson’s work has focused on, among other things, developing technologies for the rapid fabrication of DNA molecules. In 2009, he spun out some of his work into .Gen9, which aims to boost synthetic-biology innovation by offering scientists more cost-effective tools and resources.
Headquartered in Cambridge, Massachusetts, Gen9 has developed a method for synthesizing DNA on silicon chips, which significantly cuts costs and accelerates the creation and testing of genes. Commercially available since 2013, the platform is now being used by dozens of scientists and commercial firms worldwide.
Synthetic biologists synthesize genes by combining strands of DNA. These new genes can be inserted into microorganisms such as yeast and bacteria. Using this approach, scientists can tinker with the cells’ metabolic pathways, enabling the microbes to perform new functions, including testing new antibodies, sensing chemicals in an environment, or creating biofuels.

But conventional gene-synthesizing methods can be time-consuming and costly. Chemical-based processes, for instance, cost roughly 20 cents per base pair — DNA’s key building block — and produce one strand of DNA at a time. This adds up in time and money when synthesizing genes comprising 100,000 base pairs.

Gen9’s chip-based DNA, however, drops the price to roughly 2 cents per base pair, Jacobson says. Additionally, hundreds of thousands of base pairs can be tested and compiled in parallel, as opposed to testing and compiling each pair individually through conventional methods.

This means faster testing and development of new pathways — which usually takes many years — for applications such as advanced therapeutics, and more effective enzymes for detergents, food processing, and biofuels, Jacobson says. “If you can build thousands of pathways on a chip in parallel, and can test them all at once, you get to a working metabolic pathway much faster,” he says.

Over the years, Jacobson and Gen9 have earned many awards and honors. In November, Jacobson was also inducted into the National Inventors Hall of Fame for co-inventing E Ink, the electronic ink used for Amazon’s Kindle e-reader display.

Scaling gene synthesizing Throughout the early-and mid-2000s, a few important pieces of research came together to allow for the scaling up of gene synthesis, which ultimately led to Gen9.

First, Jacobson and his students Chris Emig and Brian Chow began developing chips with thousands of “spots,” which each contained about 100 million copies of a different DNA sequence.

Then, Jacobson and another student, David Kong, created a process that used a certain enzyme as a catalyst to assemble those small DNA fragments into larger DNA strands inside microfluidics devices — “which was the first microfluidics assembly of DNA ever,” Jacobson says.

Despite the novelty, however, the process still wasn’t entirely cost effective. On average, it produced a 99 percent yield, meaning that about 1 percent of the base pairs didn’t match when constructing larger strands. That’s not so bad for making genes with 100 base pairs. “But if you want to make something that’s 10,000 or 100,000 bases long, that’s no good anymore,” Jacobson says.

Around 2004, Jacobson and then-postdoc Peter Carr, along with several other students, found a way to drastically increase yields by taking a cue from a natural error-correcting protein, Mut-S, which recognizes mismatches in DNA base pairing that occur when two DNA strands form a double helix. For synthetic DNA, the protein can detect and extract mismatches arising in base pairs synthesized on the chip, improving yields. In a paper published that year in Nucleic Acids Research, the researchers wrote that this process reduces the frequency of errors, from one in every 100 base pairs to around one in every 10,000.

With these innovations, Jacobson launched Gen9 with two co-founders: George Church of Harvard University, who was also working on synthesizing DNA on microchips, and Drew Endy of Stanford University, a world leader in synthetic-biology innovations.

Together with employees, they created a platform called BioFab and several other tools for synthetic biologists. Today, clients use an online portal to order gene sequences. Then Gen9 designs and fabricates those sequences on chips and delivers them to customers. Recently, the startup updated the portal to allow drag-and-drop capabilities and options for editing and storing gene sequences.

This allows users to “make these very extensive libraries that have been inaccessible previously,” Jacobson says.

Fueling big ideas

Many published studies have already used Gen9’s tools, several of which are posted to the startup’s website. Notable ones, Jacobson says, include designing proteins for therapeutics. In those cases, the researcher needs to make 10 million or 100 million versions of a protein, each comprising maybe 50,000 pieces of DNA, to see which ones work best.

Instead of making and testing DNA sequences one at a time with conventional methods, Gen9 lets researchers test hundreds of thousands of sequences at once on a chip. This should increase chances of finding the right protein, more quickly. “If you just have one shot you’re very unlikely to hit the target,” Jacobson says. “If you have thousands or tens of thousands of shots on a goal, you have a much better chance of success.

Currently, all the world’s synthetic-biology methods produce only about 300 million bases per year. About 10 of the chips Gen9 uses to make DNA can hold the same amount of content, Jacobson says. In principle, he says, the platform used to make Gen9’s chips — based on collaboration with manufacturing firm Agilent — could produce enough chips to cover about 200 billion bases. This is about the equivalent capacity of GenBank, an open-access database of DNA bases and gene sequences that has been constantly updated since the 1980s.

Such technology could soon be worth a pretty penny: According to a study published in November by MarketsandMarkets, a major marketing research firm, the market for synthesizing short DNA strands is expected to reach roughly $1.9 billion by 2020.

Still, Gen9 is pushing to drop costs for synthesis to under 1 cent per base pair, Jacobson says. Additionally, for the past few years, the startup has hosted an annual G-Prize Competition, which awards 1 million base pairs of DNA to researchers with creative synthetic-biology ideas. That’s a prize worth roughly $100,000.

The aim, Jacobson says, is to remove cost barriers for synthetic biologists to boost innovation. “People have lots of ideas but are unable to try out those ideas because of cost,” he says. “This encourages people to think about bigger and bigger ideas.”

ORIGINAL: .MIT News
Rob Matheson | MIT News Office
December 10, 2015

viernes, 30 de agosto de 2013

Rice Gene Digs Deep To Triple Yields In Drought

ORIGINAL: Asian Scientist
By Science and Development Network | Featured Research
August 6, 2013

Japanese researchers have identified a gene that triples the yield of rice during droughts by giving rice plants deeper roots.

Asian Scientist (Aug. 6, 2013) - A gene that gives rice plants deeper roots can triple yields during droughts, according to Japanese researchers writing in Nature Genetics this week (4 August).

Rice is a staple food for nearly half of the world’s population, but is also particularly susceptible to drought owing to its shallow roots, researchers say.

The new study shows that by pointing roots down instead of sideways, the Deeper Rooting 1 (DRO1) gene results in roots that are nearly twice as deep as those of standard rice varieties.


If rice adapts to or avoids drought conditions using deeper roots, it can get water and nutrients from the deep soil layers,” says the study’s lead author Yusaku Uga, a researcher with Japan’s National Institute of Agrobiological Sciences.

Uga and his team found that in moderate drought conditions, the yield of rice with DRO1 was double that of the shallow-rooted rice variety. Under severe drought conditions, this increased to 3.6 times greater.

The most important point is that we had rice grains produced under drought conditions,” says Uga.

When rice crops just tolerate drought, they cannot get water and nutrients, resulting in a kind of survival mode.”

The DRO1 gene occurs naturally in more than 60 rice varieties. For the study, the research team crossbred a rice variety carrying DRO1 with a shallow-rooted variety and then bred the offspring together to produce a rice crop in which DRO1 was uniformly present.

The International Rice Research Institute (IRRI) estimates that an additional 8-10 million tonnes of rice will be needed each year to keep rice prices affordable at around US$300 per tonne. Finding a drought-resistant variety of rice may be key to attaining this goal, according to researchers.

Drought is the most widespread and damaging of all environmental stresses,” says Sophie Clayton, head of communications at IRRI.

In some states in India, severe drought can cause as much as 40 per cent yield loss [in rice crops]. Moreover, with the onset of climate change, droughts may become more frequent and more severe.

The article can be found at: Uga et al. (2013) Control Of Root System Architecture By DEEPER ROOTING 1 Increases Rice Yield Under Drought Conditions.

——

Source: Science and Development Network; Photo: IRRI.
Disclaimer: This article does not necessarily reflect the views of AsianScientist or its staff.

jueves, 1 de agosto de 2013

Scientists identify gene that controls aggressiveness in breast cancer cells

ORIGINAL: MIT
by Nicole Giese Rura

July 3, 2013


Cells from basal cancers are able to switch relatively easily into cancer stem cell (CSC) state, unlike luminal breast cancer cells, which tend to remain in the -. The gene ZEB1 is critical for this conversion. The difference in ZEB1’s effects is due to the way the gene is marked in the two types of cancers. In luminal breast cancer cells, the ZEB1 gene is occupied with modifications that shut it down. But in basal breast cancer cells, ZEB1’s state is more tenuous, with repressing and activating markers coexisting on the gene. When these cells are exposed to certain signals, including those from TGFß, the repressive marks are removed and ZEB1 is expressed, thereby converting the basal non-CSCs into CSCs.

CAMBRIDGE, Mass. – In a discovery that sheds new light on the aggressiveness of certain breast cancers, Whitehead Institute researchers have identified a transcription factor, known as ZEB1, that is capable of converting non-aggressive basal-type cancer cells into highly malignant, tumor-forming cancer stem cells (CSCs). Intriguingly, luminal breast cancer cells, which are associated with a much better clinical prognosis, carry this gene in a state in which it seems to be permanently shut down.

The researchers, whose findings are published this week in the journal Cell, report that the ZEB1 gene is held in a poised state in basal non-CSCs, such that it can readily respond to environmental cues that consequently drive those non-CSCs into the dangerous CSC state. Basal-type breast carcinoma is a highly aggressive form of breast cancer. According to a 2011 epidemiological study, the 5-year survival rate for patients with basal breast cancer is 76%, compared with a roughly 90% 5-year survival rate among patients with other forms of breast cancer.

We may have found a root source, maybe the root source, of what ultimately determines the destiny of breast cancer cells—their future benign or aggressive clinical behavior,” says Whitehead Founding Member Robert Weinberg, who is also a professor of biology at MIT and Director of the MIT/Ludwig Center for Molecular Oncology.

Transcription factors are genes that control the expression of other genes, and therefore have a significant impact on cell activities. In the case of ZEB1, it has an important role in the so-called epithelial-to-mesenchymal transition (EMT), during which epithelial cells acquire the traits of mesenchymal cells. Unlike the tightly-packed epithelial cells that stick to one another, mesenchymal cells are loose and free to move around a tissue. Previous work in the Weinberg lab showed that adult cancer cells passing through an EMT are able to self-renew and to seed new tumors with high efficiency, hallmark traits of CSCs.

Other earlier work led by Christine Chaffer, a postdoctoral researcher in the Weinberg lab, demonstrated that cancer cells are able to spontaneously become CSCs. Now Chaffer and Nemanja Marjanovic have pinpointed ZEB1, a key player in the EMT, as a gene critical for this conversion in breast cancer cells.

Breast cancers are categorized into at least five different subgroups based on their molecular profiles. More broadly these groups can be subdivided into the less aggressive ‘luminal’ subgroup or more aggressive ‘basal’ subgroup. The aggressive basal-type breast cancers often metastasize, seeding new tumors in distant parts of the body. Patients with basal breast cancer generally have a poorer prognosis than those with the less aggressive luminal-type breast cancer.

Chaffer and Marjanovic, a former research assistant in the Weinberg lab, studied non-CSCs from luminal- and basal-type cancers and determined that cells from basal cancers are able to switch relatively easily into CSC state, unlike luminal breast cancer cells, which tend to remain in the non-CSC state.

The scientists determined that the difference in ZEB1’s effects is due to the way the gene is marked in the two types of cancers. In luminal breast cancer cells, the ZEB1 gene is occupied with modifications that shut it down. But in basal breast cancer cells, ZEB1’s state is more tenuous, with repressing and activating markers coexisting on the gene. When these cells are exposed to certain signals, including those from TGFß, the repressive marks are removed and ZEB1 is expressed, thereby converting the basal non-CSCs into CSCs.

So what does this new insight mean for treating basal breast cancer?

Well, we know that these basal breast cancer cells are very plastic and we need to incorporate that kind of thinking into treatment regimes,” says Chaffer. “As well as targeting cancer stem cells, we also need to think about how we can prevent the non-cancer stem cells from continually replenishing the pool of cancer stem cells. For example, adjuvant therapies that inhibit this type of cell plasticity may be a very effective way to keep metastasis at bay.

Marjnaovic agrees but cautions that the model may not be applicable for every cancer.

This is an example of how adaptable cancer cells can be,,” says Marjanovic, who is currently a research assistant at the Broad Institute. “We have yet to determine if ZEB1 plays a similar role in all cancer types, but the idea that cancer cells reside in a poised state that enables them to adapt to changing environments may be a mechanism used by many cancers to increase their aggressiveness.


This work is supported the Advanced Medical Research Foundation (AMRF), Breast Cancer Research Foundation, and National Institutes of Health (NIH) grants HG002668 and CA146445.

Written by Nicole Giese Rura

* * *

Robert Weinberg’s primary affiliation is with Whitehead Institute for Biomedical Research, where his laboratory is located and all his research is conducted. He is also a professor of biology at Massachusetts Institute of Technology and Director of the MIT/Ludwig Center for Molecular Oncology.

* * *

Full Citation:

“Poised chromatin at the ZEB1 promoter enables breast cancer cell plasticity and enhances tumorigenicity”

Cell, July 3, 2013.

Christine L Chaffer (1*), Nemanja D Marjanovic (1*), Tony Lee (1), George Bell (1), Celina G Kleer (2), Ferenc Reinhardt (1), Ana C D’Alessio (1), Richard A Young (1,3), and Robert A Weinberg (1,4).

1.Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA

2. University of Michigan Medical School, Department of Pathology, Ann Arbor MI, 48109, USA

3.Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA

4.Ludwig MIT Center for Molecular Oncology, Cambridge, MA 02139, USA

*These authors contributed equally to this work.


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