iansmith
Apr21-04, 05:52 PM
Single gene knockout in dual maternal oocyte results in viable mice, but some doubt study | By Cathy Holding
A study published in the advance online publication of Nature today (April 21) reports the first mouse created by parthenogenesis. But a leading researcher called the results very confusing, saying they raise more questions than answers.
Tomohiro Kono and colleagues from the Tokyo University of Agriculture, Japan, report that they knocked out one allele of H19—a maternally expressed gene thought to function as A noncoding mRNA that blocks IN CIS the expression of Igf2—in an oocyte derived solely from two maternal genomes. A normally developed and viable parthenote resulted, suggesting a pivotal role for the paternally imprinted H19 gene in allowing Igf2 expression from the paternal allele and controlling the requirement for a paternal genome, according to the authors.
“When you put these two sets of chromosomes together functionally, the individual would have a father-like genome with the original mother genome, and therefore it works and gives rise to a live offspring,” Patrick Tam, head of the embryology unit at the Children's Medical Research Institute, Westmead, Australia, who wrote an accompanying News and Views article, told The Scientist.
In prior experiments, the Tokyo group had used a maternally imprinted genome and a neutral genome, which still proved to be lethal, according to Wolf Reik, head of developmental genetics and imprinting at the Babraham Institute in Cambridge, UK. “What they are trying to do now is convert the neutral genome into a paternal one by giving it this H19 deletion allele, which allows the neutral genome to express Igf2—and this is clearly a key event that needs to happen here,” said Reik, who was not involved in the study.
http://www.biomedcentral.com/news/20040421/01
A study published in the advance online publication of Nature today (April 21) reports the first mouse created by parthenogenesis. But a leading researcher called the results very confusing, saying they raise more questions than answers.
Tomohiro Kono and colleagues from the Tokyo University of Agriculture, Japan, report that they knocked out one allele of H19—a maternally expressed gene thought to function as A noncoding mRNA that blocks IN CIS the expression of Igf2—in an oocyte derived solely from two maternal genomes. A normally developed and viable parthenote resulted, suggesting a pivotal role for the paternally imprinted H19 gene in allowing Igf2 expression from the paternal allele and controlling the requirement for a paternal genome, according to the authors.
“When you put these two sets of chromosomes together functionally, the individual would have a father-like genome with the original mother genome, and therefore it works and gives rise to a live offspring,” Patrick Tam, head of the embryology unit at the Children's Medical Research Institute, Westmead, Australia, who wrote an accompanying News and Views article, told The Scientist.
In prior experiments, the Tokyo group had used a maternally imprinted genome and a neutral genome, which still proved to be lethal, according to Wolf Reik, head of developmental genetics and imprinting at the Babraham Institute in Cambridge, UK. “What they are trying to do now is convert the neutral genome into a paternal one by giving it this H19 deletion allele, which allows the neutral genome to express Igf2—and this is clearly a key event that needs to happen here,” said Reik, who was not involved in the study.
http://www.biomedcentral.com/news/20040421/01