Why your fertility cells must have 'radio silence'

January 29, 2008

Researchers in Kobe, Japan, and Montreal, Canada, have uncovered a previously unknown mechanism which causes embryonic germ cells – which later develop into sperm or ova – to go through a period of “transcriptional silence,” during which information from the cell’s DNA cannot be copied. Without this important phase, unique to cells of this type, an organism produces sterile offspring.

The study was conducted by a team led by Dr. Akira Nakamura at the RIKEN Center for Developmental Biology (CDB) in Kobe and by Dr. Paul Lasko, Chair of McGill University’s Department of Biology. Their results were published in January, 2008, in the journal Nature.

“A fundamental characteristic of embryonic germ cells in all organisms is that they don't transcribe their own genes for a certain time during embryonic development,” Dr. Lasko explained. “They are transcriptionally silent; that's what makes them special. It's not fully understood why this is the case, but if that silencing doesn't happen, then the germ cells don't work. They don't migrate correctly and they don't make their way into the gonads.”

Dr. Nakamura was a post-doctoral fellow in Dr. Lasko’s lab in the mid-1990s when they co-discovered the Polar Granule Component (PGC) gene in drosophila, commonly known as the fruit fly. If the mother fly lacks PGC, her offspring will be unable to produce germ cells. Initially, Dr. Lasko said, they discovered that the PGC gene produced an RNA, but they did not believe it produced any proteins. Using current technology, Dr. Nakamura discovered that PGC does indeed produce a protein which regulates Transcription Elongation Factor B (TEF-B), the genetic machinery that expresses proteins.

“It’s a very small, 71-amino acid protein,” Dr. Lasko explained. “The average length of a protein is about 400 to 500 amino acids, so this is extremely small. Back when we did the initial research, there weren't very many genes known that encoded such a short protein. The significance of this is that Nakamura has shown that this little protein seems to be the key regulator that keeps gene expression shut off in germ cells.”

Mutant fruit flies without the ability to produce the protein produce sterile offspring which produce no sperm or eggs.

“What the study argues is that this regulation of TEF-B might be very important for germ cell development in a variety of organisms. That's something people will want to look at in mammals,” Dr. Lasko said.

Source: McGill University

Explore further: Time travel with the molecular clock

Related Stories

Time travel with the molecular clock

November 23, 2015

Migration isn't a new phenomenon, but new insights suggest that modern-day Europeans actually have at least three ancestral populations. This finding was published by Johannes Krause and prominently featured on the cover ...

Scientists create malaria-blocking mosquitoes

November 23, 2015

Using a groundbreaking gene editing technique, University of California scientists have created a strain of mosquitoes capable of rapidly introducing malaria-blocking genes into a mosquito population through its progeny, ...

Gut microbiota regulates antioxidant metabolism

November 6, 2015

A recently published study shows that gut microbiota regulates the glutathione and amino acid metabolism of the host. Glutathione is a key antioxidant, found in every cell in our body. Deficiency of glutathione contributes ...

Deep-diving whales could hold answer for synthetic blood

September 25, 2015

The ultra-stable properties of the proteins that allow deep-diving whales to remain active while holding their breath for up to two hours could help Rice University biochemist John Olson and his colleagues finish a 20-year ...

Recommended for you

Amazon deforestation leaps 16 percent in 2015

November 28, 2015

Illegal logging and clearing of Brazil's Amazon rainforest increased 16 percent in the last year, the government said, in a setback to the aim of stopping destruction of the world's greatest forest by 2030.

CERN collides heavy nuclei at new record high energy

November 25, 2015

The world's most powerful accelerator, the 27 km long Large Hadron Collider (LHC) operating at CERN in Geneva established collisions between lead nuclei, this morning, at the highest energies ever. The LHC has been colliding ...

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

not rated yet Jan 29, 2008
maybe this has something to do with stem cells?

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.