Featured Research

from universities, journals, and other organizations

Inheriting Mitochondria: Where does your father's go?

Date:
May 15, 2014
Source:
Weizmann Institute of Science
Summary:
While it's common knowledge that all organisms inherit their mitochondria -- the cell's "power plants" -- from their mothers, it hasn't been clear what happens to all the father's mitochondria. Surprisingly, how -- and why -- paternal mitochondria are prevented from getting passed on to their offspring after fertilization is still shrouded in mystery; the only thing that's certain is that there must be a compelling reason, seeing as this phenomenon has been conserved throughout evolution. A crucial step in fertilization, and this issue, is now better understood, thanks to recent research.

It's common knowledge that all organisms inherit their mitochondria -- the cell's "power plants" -- from their mothers. But what happens to all the father's mitochondria? Surprisingly, how -- and why -- paternal mitochondria are prevented from getting passed on to their offspring after fertilization is still shrouded in mystery; the only thing that's certain is that there must be a compelling reason, seeing as this phenomenon has been conserved throughout evolution.

Now, Dr. Eli Arama and a team in the Weizmann Institute's Molecular Genetics Department have discovered special cellular vesicles that originate in the female fruit flies' egg and which actively seek out and destroy the father's mitochondria upon fertilization.

This study, recently published in Development Cell, may help shed light on the prevailing theories. One holds that it is an active process in which paternal mitochondria are selectively degraded by a "self-eating" system known as autophagy, in which vesicles called autophagosomes engulf the cell's unwanted structures. But the autophagy study was conducted on worms (C. elegans) whose sperm are quite different from the long, flagellated "head" and "tail" structures of both mammalian and fruit-fly sperm. The tail comprises the mitochondria: a long tube attached to, or coiled around, the tail's skeletal structure. How would the tiny autophagosome engulf such a large structure -- about 2 mm long in the fruit fly?

A second theory, based mainly on mouse models, states that the absence of paternal mitochondria is due to a passive process of dilution in the sea of maternal mitochondria. But that could not explain why certain genetic markers related to autophagy were still detected on the paternal mitochondria after fertilization.

Enter the egg's special cellular vesicles. The Weizmann team, led by Ph.D. students Liron Gal and Yoav Politi in Arama's group, together with former senior intern Yossi Kalifa and former Ph.D. student Liat Ravid, and with the assistance of Prof. Zvulun Elazar of the Biological Chemistry Department, found that as soon as the sperm enters the egg, the cellular vesicles -- already present in the fruit fly egg -- immediately attract to the sperm like a magnet. They then proceed to disintegrate the sperm's outer membrane and separate the mitochondria from the tail section, which is subsequently cut into smaller pieces that are then "devoured" by conventional selective autophagy.

But what were these vesicles? Close observation revealed they did not resemble an autophagosome, but rather a different type of vesicle that is usually involved in a distinct pathway. Yet these vesicles carried autophagy markers. Arama: "We were not witnessing classic autophagy machinery; these structures were too large and morphologically distinct to be typical autophagosomes."

The team's findings suggest that the egg's special cellular vesicles represent a new type of system that is a unique combination of three separate biological processes whose pathways may have diverged from their classic functions.

These new discoveries, which the scientists believe hold true for other organisms with flagellated sperm, including humans, may lead, among other things, toward an understanding of why only a quarter of IVF pregnancies carry to term. It may be that this invasive procedure somehow abrogates the ability of the egg to destroy the paternal mitochondria. Arama and team hope that further research will help shed new light on a variety of issues pertaining to paternal mitochondria, with an ultimate goal of understanding mitochondrial turnover and male fertility.


Story Source:

The above story is based on materials provided by Weizmann Institute of Science. Note: Materials may be edited for content and length.


Journal Reference:

  1. Yoav Politi, Liron Gal, Yossi Kalifa, Liat Ravid, Zvulun Elazar, Eli Arama. Paternal Mitochondrial Destruction after Fertilization Is Mediated by a Common Endocytic and Autophagic Pathway in Drosophila. Developmental Cell, 2014; 29 (3): 305 DOI: 10.1016/j.devcel.2014.04.005

Cite This Page:

Weizmann Institute of Science. "Inheriting Mitochondria: Where does your father's go?." ScienceDaily. ScienceDaily, 15 May 2014. <www.sciencedaily.com/releases/2014/05/140515095637.htm>.
Weizmann Institute of Science. (2014, May 15). Inheriting Mitochondria: Where does your father's go?. ScienceDaily. Retrieved September 20, 2014 from www.sciencedaily.com/releases/2014/05/140515095637.htm
Weizmann Institute of Science. "Inheriting Mitochondria: Where does your father's go?." ScienceDaily. www.sciencedaily.com/releases/2014/05/140515095637.htm (accessed September 20, 2014).

Share This



More Health & Medicine News

Saturday, September 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Sierra Leone's Nationwide Ebola Curfew Underway

Sierra Leone's Nationwide Ebola Curfew Underway

Newsy (Sep. 20, 2014) Sierra Leone is locked down as aid workers and volunteers look for new cases of Ebola. Video provided by Newsy
Powered by NewsLook.com
Changes Found In Brain After One Dose Of Antidepressants

Changes Found In Brain After One Dose Of Antidepressants

Newsy (Sep. 19, 2014) A study suggest antidepressants can kick in much sooner than previously thought. Video provided by Newsy
Powered by NewsLook.com
Could Grief Affect The Immune Systems Of Senior Citizens?

Could Grief Affect The Immune Systems Of Senior Citizens?

Newsy (Sep. 19, 2014) The study found elderly people are much more likely to become susceptible to infection than younger adults going though a similar situation. Video provided by Newsy
Powered by NewsLook.com
Jury Delivers Verdict in Salmonella Trial

Jury Delivers Verdict in Salmonella Trial

AP (Sep. 19, 2014) A federal jury has convicted three people in connection with an outbreak of salmonella poisoning five years ago that sickened hundreds of people and was linked to a number of deaths. (Sept. 19) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins