“Latest Stem Cells News”

While only a small portion of autism spectrum disorders (ASDs) can be traced to their genetic roots, those that can are most often part of Fragile X syndrome (FXS), the most commonly known single-gene cause of autism. FXS is associated with the loss of the FMR protein (FMRP) coded by the mental retardation gene 1, FMR1 gene.

While scientists understand the biochemical nuances of these mutations, their implications on neuronal development and function remain a mystery. To address this puzzle, HSCI Associate Faculty member Stephen Haggarty, PhD, reprogrammed a series of both mutated and non-mutated cells back into a stem cell state in which they have the ability to derive new tissues.

Haggarty and his team found that the FMR1 mutations present in the induced pluripotent stem cells (iPSCs) do not always resemble those in the naturally occurring cells from which they came. This offers valuable information as other researchers begin to design investigations using these iPSCs.

Additionally, the team used the cell lines to generate a variety of neuronal cell types. While FMRP loss did not prevent neurodevelopment, it did impact cell quality, suggesting an important role for FMRP early in human neurodevelopment. These findings will allow researchers to characterize existing drugs and develop new therapies for the treatment of some ASDs.

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Researchers have created mammalian cells containing a single set of chromosomes in research funded by the Wellcome Trust and EMBO. The technique should allow scientists to better establish the relationships between genes and their function.

Mammal cells usually contain two sets of chromosomes – one set inherited from the mother and one from the father. The genetic information contained in these chromosome sets helps determine how our bodies develop. Changes in this genetic code can lead to or increase the risk of developing disease.

To understand how our genes function, scientists manipulate the genes in animal models – such as the fruit fly, zebrafish and mice – and observe the effects of these changes. However, as each cell contains two copies of each chromosome, determining the link between a genetic change and its physical effect – or ‘phenotype’ – is immensely complex.

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Researchers from the University of Cambridge have created mammalian cells containing a single set of chromosomes for the first time in research funded by the Wellcome Trust and EMBO. The technique should allow scientists to better establish the relationships between genes and their function.

Mammal cells usually contain two sets of chromosomes – one set inherited from the mother, one from the father. The genetic information contained in these chromosome sets helps determine how our bodies develop. Changes in this genetic code can lead to or increase the risk of developing disease.

To understand how our genes function, scientists manipulate the genes in animal models – such as the fruit fly, zebrafish and mice – and observe the effects of these changes. However, as each cell contains two copies of each chromosome, determining the link between a genetic change and its physical effect – or ‘phenotype’ – is immensely complex.

Now, in research published today in the journal Nature, Drs Anton Wutz and Martin Leeb from the Wellcome Trust Centre for Stem Cell Research at the University of Cambridge report a technique which enables them to create stem cells containing just a single set of chromosomes from an unfertilised mouse egg cell. The stem cells can be used to identify mutations in genes that affect the cells’ behaviour in culture. In an additional step, the cells can potentially be implanted into the mouse for studying the change in organs and tissues.

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Stem cell transplantation in a 42-year-old HIV patient with leukemia has wiped out the virus from his body, the doctor of Berlin Charité Hospital confirms.
“The patient is fine,” said Dr. Gero Hutter, a haematologist at the Berlin Charité Hospital. “Today, two years after his transplantation, he is still without any signs of HIV disease and without antiretroviral medication.”

The doctor observed that using the stem cells from a donor who carries a unique gene mutation i.e. delta 32 ccr5 along with a tissue match, could now cure the patient from the HIV virus. Delta 32 ccr5 makes the cells resistant to HIV virus and this mutation is found in a little more than 1 percent of Caucasians.
Dr. Hutter told, “When the recipient got the new bone marrow, his cells could now block out the HIV, and, in effect, he was cured. Bone marrow transplants are high risk, so only lymphoma and leukemia patients take the risk to possibly cure their cancer.”

The study is published Wednesday in the New England Journal of Medicine.

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Each one of us receives approximately 60 new mutations in our genome from our parents.

This striking value is reported in the first-ever direct measure of new mutations coming from mother and father in whole human genomes published today.

For the first time, researchers have been able to answer the questions: how many new mutations does a child have and did most of them come from mum or dad? The researchers measured directly the numbers of mutations in two families, using whole genome sequences from the 1000 Genomes Project. The results also reveal that human genomes, like all genomes, are changed by the forces of mutation: our DNA is altered by differences in its code from that of our parents. Mutations that occur in sperm or egg cells will be ‘new’ mutations not seen in our parents.

Although most of our variety comes from reshuffling of genes from our parents, new mutations are the ultimate source from which new variation is drawn. Finding new mutations is extremely technically challenging as, on average, only 1 in every 100 million letters of DNA is altered each generation.

Previous measures of the mutation rate in humans has either averaged across both sexes or measured over several generations. There has been no measure of the new mutations passed from a specific parent to a child among multiple individuals or families.

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