Blastocyst

 

PRIMATE
CLONED
BLASTOCYST
 

Semos the Rhesus monkey

The monkey was not cloned - some of his skin cells were transformed into embryonic stem cells

Nature advance online publication 14 November 2007 | doi:10.1038/nature06357; Published online
14 November 2007

Producing primate embryonic stem cells by somatic cell nuclear transfer

J Byrne, D Pedersen, L Clepper, M Nelson, W Sanger, S Gokhale, D Wolf & S Mitalipov

Abstract

Derivation of embryonic stem (ES) cells genetically identical to a patient by somatic cell nuclear transfer (SCNT) holds the potential to cure or alleviate the symptoms of many degenerative diseases while circumventing concerns regarding rejection by the host immune system. However, the concept has only been achieved in the mouse, whereas inefficient reprogramming and poor embryonic development characterizes the results obtained in primates. Here, we used a modified SCNT approach to produce rhesus macaque blastocysts from adult skin fibroblasts, and successfully isolated two ES cell lines from these embryos. DNA analysis confirmed that nuclear DNA was identical to donor somatic cells and that mitochondrial DNA originated from oocytes. Both cell lines exhibited normal ES cell morphology, expressed key stem-cell markers, were transcriptionally similar to control ES cells and differentiated into multiple cell types in vitro and in vivo. Our results represent successful nuclear reprogramming of adult somatic cells into pluripotent ES cells and demonstrate proof-of-concept for therapeutic cloning in primates.


Associated Press Online

Scientists Report Cloning Monkey Embryos

By MALCOLM RITTER – 32 minutes ago

NEW YORK (AP) — American scientists reported Wednesday that they had cloned embryos from a 9-year-old male monkey and derived stem cells from them, reaching a long-sought goal that may pay off someday in new treatments for people.

The work was published online by the journal Nature, which took the unusual step of asking another team of researchers to verify the work before publication. That reflects the legacy of a spectacular fraud in stem cell research from South Korea several years ago.

The new work is important because someday researchers hope to use such a process in humans to make transplant tissue that’s genetically matched to patients, thus avoiding the risk of rejection.

Scientists had tried for years to produce stem cells through cloning in monkeys, because the animals are so closely related to humans and so provide a good way to study the process. But until now, it hasn’t worked.

The advance is reported by Shoukhrat Mitalipov of the Oregon National Primate Research Center in Portland with colleagues there and elsewhere. Some media outlets, including The Associated Press, had reported their success earlier, based on a presentation at a scientific meeting.

The scientists combined DNA from skin cells of the monkey, a rhesus macaque, with unfertilized monkey eggs that had their own DNA removed. The eggs were grown into early embryos, from which stem cells were removed.

The researchers cautioned that even if their procedure could be used to produce human stem cells, it’s far too inefficient to be used in medicine. Human unfertilized eggs are in short supply and are cumbersome to obtain. The monkey work required 304 eggs from 14 female macaques to produce just two batches of stem cells, they wrote.

Still, Dr. George Daley of the Harvard Stem Cell Institute, who was familiar with the work, told the AP it was a “a very important demonstration” that the process is feasible in primates, the group that includes monkeys and humans.

Nature also published a verification of the results by an Australian team. In an e-mail to the AP, the journal said one reason was the highly publicized 2004 fraud that came out of South Korea, where researchers claimed to have produced stem cells from a cloned human embryo.

The journal emphasized that its request didn’t indicate mistrust of scientists in the cloning field. Instead, the statement said, because of “questions will likely be raised about the veracity of the (American) experiments, given recent history in the cloning field, we view this as a relatively straightforward way of putting these questions to rest.”

The Australian study, by David Cram and others at the Monash University, used DNA analysis of the male macaque, the two monkeys that donated eggs for creating the embryos, and the stem cells. The result “demonstrates beyond any doubt” that the stem cells came from cloned embryos, the Australians wrote in their Nature paper.



Dr. Mitalipov uses a new technique he calls Oosight to remove nuclei, utilizing "polarized light to illuminate/visualize cells in real-time".

Nature advance online publication 14 November 2007 | doi:10.1038/nature06357; Published online
 

 

 

N.B Semos” is the name of the monkey-deity in the film, Planet of the Apes.


From Dolly to Semos

1996 Birth of Dolly the sheep, above, the first mammal cloned with somatic cell nuclear transfer technique. The achievement was announced in 1997

2002 First cloned cat, Cc or Copy Cat, born. Other animals to be cloned include rats, mice and cows

2002 Raelian cult claims birth of first cloned human baby. Story discounted as fantasy

2004 South Korean team led by Woo Suk Hwang announces first cloned human embryo

2005 Hwang’s team announces further human clones, from which stem cells have been extracted

2005 Scientists at Newcastle University produce cloned human embryo, but it dies before stem cells can be removed

2005 Hwang’s human research shown to have been faked. His papers are withdrawn by the journals that published them

2007 Announcement that US scientists have cloned monkey embryos and extracted stem cells