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Wednesday, January 12, 2011

Two Important "D" Genes -- DYRK1A and DSCR1

Science is full of long names shortened by using acronyms. Don't let it bother you. Just roll with it. When scientists came up with fun names, like sonic hedgehog (after the video game), they got in trouble because then it becomes a disease of the same name. Ooops! So, for the most part scientist are stuck naming proteins, and other chemicals by their function.

The 2 we are going to look at are DYRK1A and DSCR1.

DYRK1A is a gene on the 21st chromosome It's name is really confusing. It literally stands for.....Dual specificity tyrosine-phosphorylation-regulated kinase 1A. Now you know why everyone just calls it DYRK1A.

The gene DYRK1A gives the instruction for the cell to make an enzyme by the same name, DYRK1A. Just for those who skipped biology class, enzymes are mainly proteins, that speed up certain chemical reactions. Enzymes are used inside of cells to aid in cell growth and reproduction.

An example of enzymes that most people are aware of are digestive enzymes. They speed up the breakdown of our food.

Back to DYRK1A and DSCR1......

DSCR1 is another gene on the 21st chromosome. And it stands for 'Down syndrome critical region 1'. Everyone has this gene. Stanford's DS mice had the symptoms of down syndrome even if this was the only gene that was tripled.

There are a few more letters you have to follow. NFATc. I know, I know.... but this is the key to the problem in this chemical pathway in Down syndrome. NFATc (or Nuclear factor of activated T-cells, cytoplasmic 1) is a protein that is very, very important in neurogenesis (new nerves being created), cell proliferation, cytokinesis (literally means cell movement but is involved in cell division) and cellular differentiation (a cell becomes a certain tissue for example, a nerve cell or a skin cell).

Now let's get to the nuts and bolts of these genes/enzymes and what they do. I found a picture that shows exactly what is going on.

The picture on the left is a picture of a normal functioning cell. There is an {'a'} above it. The picture on the right is of a Down syndrome cell and has a {b} above it.

Notice how calcium comes into the cell at the top and triggers a pathway called Calcineurin (green arrow) and that in turn triggers NFATc which is necessary for cell growth.

In the Down syndrome cell, {b}, there is 1.5 times the amount of the 2 genes discussed above. Remember they are just letters. DSCR1 (pink oval) and DYRK1A (pink oval). The DSCR1 turns down (as in volume) the Calcineurin pathway (red sideways T) and at the same time DYRK1A pulls the NFATc (green oval) out of the nucleus.

The abnormal balance limits cell growth and proliferation. So, these genes are really disrupting new nerve growth, healthy cell production and normal regeneration of cells. What does this mean for Down syndrome? We will delve into the consequences of the imbalance tomorrow.

1 comment:

  1. Teresa, Thank you so so much for breaking all of this down for us to better understand what is happening in the bodies of our kids.