[Guest post] Tit for tet: Tet3 regulates neuron activity through epigenetic changes

Please welcome Eat, Read, Science’s first guest blogger Julia Turan! Today she’ll be sharing a cool new paper looking at how changes in our DNA change the way our neurons talk to one another.

Sequence the human genome. Check. Now all that’s left is to understand how the letters of our DNA alphabet are accessed in the context of different types of cells and microscopic environments. Completing the sequence was no small feat but we have plenty of work ahead. This field is known as epigenetics: the study of factors—inside or outside our body limits—that turn genes on or off and influences how our cells read the genome.

Nature and nurture. Two words frequently tossed around in biology. Epigenetics takes these formerly opposing concepts and swirls them together. Our nature is being nurtured. Our experiences are altering the expression of our DNA. Really let that sink in.

A term coined by C.H. Waddington (known as ‘Wad’ to his friends) in 1942, epigenetics was first studied in embryonic development. As we morph from wad to body (pun intended), cells with the same DNA blueprint become part of team lung, blood, brain, etc. Epigenetic mechanisms control this differentiation of cells. There are two important traits of these changes: 1) the DNA sequence is not directly altered, rather its expression—how it is read out and turned into a protein—is; and 2) these changes can persist after the cell divides and even in the organism’s progeny.

Thanks to Hongjun Song and his team at Johns Hopkins University, we now know that experience also influences genetic expression in the incredible three-pound clump beneath our skulls. Their research showed that these changes don’t just happen during stress, aging or neurodegenerative diseases. They are happening in all of our brains at this very moment. The chemical structure of the DNA in your brain is actively regulated in response to what you’re experiencing. These processes are essential to the stability of our brain circuits and potentially its disruption during disease. Continue reading

The curious case of Neisseria and the seven-carbon sugar

A scanning electron micrograph showing Neisseria gonorrheae bacteria (blue) infecting a type of human immune cell called a neutrophil (gold). (Image: Ryan Gaudet)
A scanning electron micrograph showing Neisseria gonorrhoeae bacteria (blue) infecting a type of human immune cell called a neutrophil (gold). (Image: Ryan Gaudet)

Walking into the little lunchroom in the back of the lab, I am greeted by a row of empty wine bottles. Celebratory drinks in the lab usually mean a manuscript’s been accepted for publication and when there’s that many empty bottles, you know it must be a pretty good journal. As I attempt to work out a wine to impact factor conversion in my head, the lab door opens and Ryan Gaudet (pronounced good-ie) walks in. Gaudet, a PhD student in the lab of Dr. Scott Gray-Owen at the University of Toronto, is the lead author of a paper recently published in the journal Science about a new signalling molecule produced by the bacteria Neisseria gonorrhoeae. It was for this paper that he and his labmates were celebrating.

To fully appreciate and understand this paper, we need to go back more than a decade to the early 2000s, when Adrienne Chen, an undergraduate student working in the Gray-Owen lab, noticed something peculiar: when cells infected with HIV were exposed to N. gonorrhoeae, HIV genes suddenly turned on and normally silent genes became expressed. This was a compelling finding because co-infection of HIV with the sexually transmitted infection gonorrhoea (caused by N. gonorrhoeae) is known to increase HIV shedding and enhance male-to-female transmission. A few years later, the mysteries of the gonorrhoea-HIV relationship drew Dr. Rebecca Malott, a postdoctoral fellow, to the Gray-Owen lab where she began a project aimed at trying to figure out how Neisseria bacteria turned on HIV gene expression.

That’s when the detective work began. Continue reading

Looking back in time: newly discovered debris ring could shed light on early Solar System

Image of the star HD 115600 (position indicated by a cross) with a bright ring of debris orbiting it. (Image: Thayne Currie)
The star HD 115600 (position indicated by a cross) with a bright ring of debris orbiting it. (Image: Thayne Currie)

How did our Solar System evolve to its current state?

That’s a difficult question to answer. Since the formation of the Solar System roughly 4.6 billion years ago, it has been in a state of constant change and evolution. Moons formed and planets shifted. Studying the evolution of the Solar System has been tricky because, well, we weren’t around to see it happen. While unearthing skeletons and imprints have helped us understand the evolution of plants and animals, similar records are hard to come by for the Solar System. Now, an international team of researchers has discovered a disc-shaped region of debris that can help shed light on how our Solar System evolved.

The newly discovered ring of debris is similar to the Kuiper Belt, a region of our Solar System located just beyond Neptune’s orbit. It contains a number of dwarf planets, including Pluto, as well as many leftover remnants from when planets were formed in the early Solar System. “If we understand the evolution and composition of the Kuiper Belt, that gives us good clues to understanding the earlier stages of the Solar System’s evolution,” says Dr. Thayne Currie, the lead author of the study. “You can almost think of it like a fossil record of the Solar System.” Continue reading