Injecting Worms

This is what my computer captures under my microscope when I inject a worm.
This is what my computer captures under my microscope when I inject a worm.

I gave an extra post about one of my jobs. It seems fair to cover the other job as well at some point!

I study introns in C. elegans worms, but how do I get the specific introns in the worms?

I need introns in specific placements in specific genes in order to study them with scientific accuracy.

The gene we are studying is simple. If the worms are put in a solution called X-gluc, they turn blue.

Based on where our enhancing intron is in the worm we expect it to turn more blue if the intron is closer to the start of the gene or less blue if it is near the end.

So I have these genes that I’m putting into the worm. They get in by injecting them like you see in the picture.

The needle of DNA is aimed at the gonad of the worm.

C. elegans worms are hermaphrodites. They contain sperm and eggs and they self-fertilize.

The worms are “male” at first, producing a bunch of sperm.

Later on they produce eggs and then they fertilize their own eggs with the sperm stored in their body.

Since they contain both genitalia the whole area is referred to as the gonad.

I aim my injection at the gonad, hoping that the DNA I’m injecting will get into the fertilized eggs.

Then the injected worm is put on a plate with lots of food and I hope that its babies will have the injected DNA.

But I don’t test for “blueness” immediately.

When a worm is first injected, the DNA is inside its cells, but not necessarily integrated into the cell’s chromosomes. I need the DNA to be a part of the chromosomes.

There are only two genes in the mix of injected DNA that will integrate. One gene is the blue gene, called GUS. The other gene is called unc119.

Unc119 is to “recover” the worms.

The worms I inject lack unc119, which is a normal gene for worms.

In a natural wild-type worm unc119 aids the development of the worm’s neural network. Without it, the worm has poor neural connections and has a lot of trouble even moving around and eating.

So the first way I test a successful injection is by looking to see if the babies of the injected worm are moving around normally or flopping around.

The normally moving ones were successful and now have unc119. They are “recovered” back to their natural wild-type state.

The floppy crippled ones did not have a successful injection. Either I missed the gonad, I didn’t inject enough DNA, or the eggs that got my injection didn’t fully germinate.

There are other markers I use to see if an injection was successful, but I’ll get to those later!

-Mister Ed

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