AUG 23, 2018 06:35 PM PDT

Link ID'ed Between Autism and Errors in the Creation of Large Proteins

WRITTEN BY: Carmen Leitch

Scientists are starting to learn more about the causes that underlie autism. Using a fragile X model, research by Ethan Greenblatt and Allan Spradling of Carnegie Institution for Science has identified a problem in the creation of proteins with large structures. These findings, which have been reported in Science, may apply to related disorders. 

Dysfunction in a gene called Fmr1 has been linked to fragile X, a developmental disorder; about one-third of affected children are on the autism spectrum. Mutations in the Fmr1 gene also lead to ovarian failure and other problems in the reproductive system. 

The Fmr1 gene is thought to be critical in protein production. When a mutation happens in the gene, it interferes with a specific process in the manufacture of certain proteins. Typically, when a protein is made, DNA is first transcribed into RNA, which is then translated into proteins. In some cases, like nerve cells, that RNA gets pre-made and then stored until it’s needed. In nerve cells, Fmr1 seems to keep that RNA from being converted immediately into protein. 

Greenblatt and Spradling wanted to know more about the function of Fmr1 in another type of cell that’s more like an egg cell - fruit fly eggs.

“Our results surprised us,” Spradling revealed. “We found that egg cells lacking Fmr1 were at first completely normal; but over time, if they were stored, they lost function much faster than stored eggs with normal Fmr1, which is reminiscent of the human ovarian failure syndrome. What’s more, when fertilized, these Fmr1-lacking eggs created offspring with severe nervous system defects, which is reminiscent of fragile X syndrome.”

This image shows an example of defects in the development of the embryonic central nervous system in stored eggs that lacked the Fmr1 gene -- stored being the key word, since un-stored eggs showed normal development. Analogous to the spinal cord, the ladder-like ventral nerve cords on the right are from stored eggs lacking in Fmr1. The image on the left is a normal ventral nerve cord with functioning Fmr1. / Credit:  Courtesy of Ethan Greenblatt and Allan Spradling.

Next, the researchers showed that when egg cells carried a dysfunctional Fmr1 gene, the expression of many proteins was reduced. In addition, a lot of those deficient proteins have been associated with autism. Another thing the proteins have in common? They are large. 

“We think that Fmr1 serves as a sort of a helper, which boosts the production of critically important large proteins that are difficult for eggs or neurons to manufacture,” Greenblatt said. “Without Fmr1, egg cells have inadequate supplies of specific large proteins and prematurely start to fail. Since Fmr1 is also important in the brain, the loss of certain large proteins associated with autism could explain the autism-like symptoms of fragile X syndrome patients.”

It is possible that other brain disorders, like ALS or Alzheimer's, might now be linked to errors in the production of large proteins. 

 

Sources: Carnegie Islands, Science

About the Author
  • Experienced research scientist and technical expert with authorships on 28 peer-reviewed publications, traveler to over 60 countries, published photographer and internationally-exhibited painter, volunteer trained in disaster-response, CPR and DV counseling.
You May Also Like
OCT 23, 2018
Genetics & Genomics
OCT 23, 2018
Sperm Can Pass Epigenetic Information Onto Offspring
We are born with a genome that doesn't change, but small modifications can be made to that genetic material throughout our lives....
NOV 01, 2018
Microbiology
NOV 01, 2018
Gut Bacteria can Have an Impact on Movement
One strain of gut bacteria can change how a fruit fly moves....
NOV 13, 2018
Neuroscience
NOV 13, 2018
Perineuronal nets and Epilepsy
Perineuronal nets (PNNs), a specialized extracellular matrix structures that surround the cell bodies and proximal...
NOV 20, 2018
Cardiology
NOV 20, 2018
What Makes Some Fats Bad
You may recall hearing at some point that there are “good fats“ and “bad fats.“ What does that really mean? But what makes one type...
NOV 26, 2018
Neuroscience
NOV 26, 2018
Most Rewarding Experiences Take The Top Spot In Memory
brain filters out neutral, inconsequential events, retaining only the memories that are useful to the future decisions....
NOV 27, 2018
Cell & Molecular Biology
NOV 27, 2018
Why Screens can Interfere With Sleep
Most of us spend a lot of time looking at some type of screen, whether it's a laptop, a phone, or another device....
Loading Comments...