Mouse stem cell line advance suggests potential for IVF-incompetent eggs

February 19, 2007

Researchers have found that mouse oocytes that fail to become fertilized during in vitro fertilization are nevertheless often capable of succeeding as "cytoplasmic donors" during a subsequent cloning step using so-called nuclear transfer. Although the implications for human eggs are not yet clear, the findings are of interest because of the ethical and practical concerns surrounding the need for fresh human oocytes for similar nuclear-transfer procedures using human cells.

The findings, reported by Teruhiko Wakayama, Sayaka Wakayama, and colleagues at RIKEN Kobe in Japan, appear in the February 20th issue of the journal Current Biology, published by Cell Press.

Human IVF is now routinely practiced in fertility clinics, but a proportion of oocytes fail to become fertilized in these procedures. In the new work, researchers examined the ability of day-old mouse oocytes that fail to become fertilized in vitro—"aged, fertilization-failure" (or AFF) oocytes—to succeed in a standard cloning procedure in which the oocyte's nucleus is removed and replaced by the nucleus of a somatic cell. Although this nuclear-transfer procedure showed a lower rate of success in the very first stages of cloning compared to nuclear transfer with fresh oocytes, the early (morulae- or blastocyst-stage) mouse embryos derived from nuclear transfer using AFF oocytes showed similar rates of success in giving rise to embryonic stem cell lines.

None of the AFF-derived mouse embryos tested were capable of developing to full term, and in general, cloning by nuclear transfer sees a low success rate even when fresh eggs are used. But the authors indicate that nuclear-transfer protocols have yet to be perfected, and that the new findings suggest that once techniques required for human nuclear transfer have been optimized, it may be possible to use oocytes that failed to fertilize during IVF attempts and would otherwise be discarded.

Source: Cell Press

Explore further: Scientists grow mouse eggs from stem cells in lab

Related Stories

Scientists grow mouse eggs from stem cells in lab

October 17, 2016

Japanese scientists said Monday they had grown mouse eggs entirely in the lab, then fertilised them to yield fertile offspring, a scientific first cautiously hailed by experts in human reproduction.

From a drop of blood, a clone

August 16, 2013

Over the last few decades, scientists have drawn upon a powerful arsenal of biotechnology techniques to establish a wide variety of genetically engineered mouse strains. These animals represent invaluable resources for studying ...

Researchers insert identification codes into mouse embryos

November 18, 2010

Spanish researchers from the Department of Cell Biology, Physiology and Immunology at Universitat Autonoma de Barcelona (UAB), in collaboration with researchers from the Institute of Microelectronics of Barcelona (IMB-CNM) ...

Reprogramming the oocyte

August 26, 2015

(—Among other things, the egg is optimized to process the sperm genome. The cytoplasmic factors that make this possible also give the egg the ability to reprogram the nuclei from other kinds of cells if these nuclei ...

Recommended for you

NASA missions harvest a passel of 'pumpkin' stars

October 27, 2016

Astronomers using observations from NASA's Kepler and Swift missions have discovered a batch of rapidly spinning stars that produce X-rays at more than 100 times the peak levels ever seen from the sun. The stars, which spin ...

Experts uncover hidden layers of Jesus' tomb site

October 27, 2016

In the innermost chamber of the site said to be the tomb of Jesus, a restoration team has peeled away a marble layer for the first time in centuries in an effort to reach what it believes is the original rock surface where ...

Shocks in the early universe could be detectable today

October 27, 2016

(—Physicists have discovered a surprising consequence of a widely supported model of the early universe: according to the model, tiny cosmological perturbations produced shocks in the radiation fluid just a fraction ...


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.