Regeneration and dedifferentiation in marine worms

     A common belief is that if you cut a worm in half, you end up with two worms. Of course this is false but not entirely. In most cases, worm can regenerate lost body parts so only one half of the worm survive.

    A study led by Florian Raible at the University of Vienna set out to understand just exactly how worms can regenerate lost body parts and to what extent. The worm they chose to experiment on was Platynereis dumerilii, a type of marine worm. The reason this worm was chosen was because most worms rely on what is called a growth zone in order to regenerate. This growth zone usually houses stem cells which are used to repair the damage caused. However, marine worms, such as Platynereis dumerilii, can regenerate without a growth zone filled with stem cells. The researchers found that Platynereis dumerilii cells went under a process called dedifferentiation in order to regenerate. Cell differentiation is what causes the different types of individual cells found in multicellular organisms that require different cells for different functions. Dedifferentiation essentially undoes cell differentiation and returns the cell to a stem cell. This allows for Platynereis dumerilii to begin regenerating its lost body parts despite the lack of a growth zone. The dedifferentiated cells then went through differentiation again, returning to their original state before dedifferentiation

    The research also revealed that Myc and Sox2, components for stem cell producing medicine, played a role in the dedifferentiation of cells. Additionally, through a process known as single-cell transcriptomics, it was found that the stem cells responsible for Platynereis dumerilii's regeneration were split into two different camps, one that formed lost tissue and neurons and another camp that formed muscles and connective tissue.

Platynereis dumerilii

    I think this study was pretty interesting not for the fact that worms can regenerate but rather the fact that cells can revert back to a type of blank slate form. The article does state that "The concept of dedifferentiation was proposed over 60 years ago, but researchers at the time lacked the tools to test this idea" and that only now could they observe this process up close. In a previous post, I covered an article that used the term "reprogramming of cells" and it has once again appeared in this article, referring to dedifferentiation. It amazes me just how much we still have left to discover and how much a single piece of data could shake the world of genetics.

Human Development Influenced by Ancient Viral Molecules

Researchers have found that certain viral molecules that have been left over from millions of years of evolution play a huge role in human' development. These left over viral molecules are essential for an embryo to differentiate into all the tissue that is present in a humans body. When they blocked the production of the RNA molecule that was responsible for this differentiation, they observed that all development abruptly stopped. They hypothesize that this viral RNA sequence infected humans long ago. Instead of being detrimental it was incorporated into their genome to serve a useful purpose. 

This new data is very useful to help us understand how we evolved certain traits that differ from some of our closely related species. Using this information can give us a clue about the origins of certain species and also show the role that viruses and bacteria played in the formation of our current genome. 

An artists rendering of a virus.

 

Stem Cells and Their Ability to Stick Together

According to an article published on Science Daily, researchers from the University of Copenhagen and the Current Biology, found that the protein Oct4 was actually responsible for the stem cells' ability to stick together. The researchers found that when stem cells separate they tend to differentiate into mature cells of different parts of the body. However, if these stem cells stick together, with the help of Oct4, then they will not differentiate and will continue on as stem cells.

University of Edinburgh found that they may be able to maintain stem cells in their purest form until needed for medical use. This research, which was published in the journal
I think that this is an absolutely remarkable find. Stem cells are a very important part of medicine and gaining a better understanding of how to maintain them can lead to so many breakthroughs in the medical field. Doctors may finally be able to treat, or even cure, degenerative diseases which plague people everywhere and we can finally be able to give people their lives back.

Autism Gene Screen Highlights Protein Network

In HHMI,  findings from University of Washington’s Jay Shendure and HHMI investigator Evan Eichler showed that nearly 40 percent of the 125 most deleterious mutations found in patients with autism affected proteins which work in concert in one central hub of interconnected metabolic activity.  This central hub is a control point for numerous developmental processes during cell differentiation and morphological development, such as the upregulation/downregulation of gene expression by the large-scale packaging of DNA, a process called chromatin remodeling.

Autism is understood to be a spectrum of neurological disorder typified by inhibited communication and social skills.  Although it has been long suspected that autistic syndromes are congenital, the exact genetic and biochemical interplay that causes the disease state remained poorly understood, with dozens to hundreds of genes implicated in its epidemiology.

However, in the latest research findings, Eichler and his colleagues studied data from the Simons Simplex Collection wherein only one member from a genealogical pedigree had autism.  The presumption became that since only one progeny had autism, then the mutation which led to the disease state was spontaneous and only occurred in the germ line of the parents, most often the father.  "By comparing the genetics of the parents, who don’t have autism, and the child who does, researchers can spot genetic differences and narrow down the list of mutations that could be responsible for the disorder in that individual."  The analysis of the Simons Simplex Collection data showed that the mutations which led to autism all involved proteins that were interconnected in a single metabolic activity hub that functioned as a control point for cell differentiation.

Further research is required to fully understand autism and its umbrella of neurological disease state, but the recent findings published in HHMI give scientists a vital staging point for their research and inquiries.

[caption id="attachment_5152" align="aligncenter" width="1051" caption="Metabolic flux."][/caption]