[Press release] Genome’s tale of ‘conquer and enslave’

From the 20 February 2015 University of Toronto press release

Toronto scientists uncovered how viral remnants helped shape control of our genes.

If genes were lights on a string of DNA, the genome would appear as an endless flicker, as thousands of genes come on and off at any given time. Tim Hughes, a Professor at the University of Toronto’s Donnelly Centre, is set on figuring out the rules behind this tightly orchestrated light-show, because when it fails, disease can occur.

Genes are switched on or off by proteins called transcription factors. These proteins bind to precise sites on the DNA that serve as guideposts, telling transcription factors that their target genes are nearby.

In their latest paper, published in Nature Biotechnology, Hughes and his team did the first systematic study of the largest group of human transcription factors, called C2H2-ZF.

Despite their important roles in development and disease, these proteins have been largely unexplored because they posed a formidable challenge for researchers.

C2H2-ZF transcription factors count over 700 proteins — around three per cent of all human genes! To make matters more complicated, most human C2H2-ZF proteins are very different from those in other organisms, like those in mice. This means that scientists could not apply insights gained from animal studies to human C2H2-ZFs.

Hughes’ team found something remarkable: the reason C2H2-ZFs are so abundant and diverse — which makes them difficult to study — is that many of them evolved to defend our ancestral genome from damage caused by the notorious “selfish DNA.”

…

 

One Step Closer to Growing a Tooth

 

Diseases and conditions where stem cell treatment is promising or emerging. (See Wikipedia:Stem cell#Treatments). Bone marrow transplantation is, as of 2009, the only established use of stem cells. Model: Mikael Häggström. To discuss image, please see Template talk:Häggström diagrams (Photo credit: Wikipedia)

 

From the 20 July 2012 article at Science News Daily

 

To build a tooth, a detailed recipe to instruct cells to differentiate towards proper lineages and form dental cells is needed. Researchers in the group of Professor Irma Thesleff at the Institute of Biotechnology in Helsinki, Finland have now found a marker for dental stem cells. They showed that the transcription factor Sox2 is specifically expressed in stem cells of the mouse front tooth…

..

Despite the development of new bioengineering protocols, building a tooth from stem cells remains a distant goal. Demand for it exists as loss of teeth affects oral health, quality of life, as well as one’s appearance. To build a tooth, a detailed recipe to instruct cells to differentiate towards proper lineages and form dental cells is needed. However, the study of stem cells requires their isolation and a lack of a specific marker has hindered studies so far.

Researchers in the group of Professor Irma Thesleff at the Institute of Biotechnology in Helsinki, Finland have now found a marker for dental stem cells. They showed that the transcription factor Sox2 is specifically expressed in stem cells of the mouse incisor (front tooth). The mouse incisor grows continuously throughout life and this growth is fueled by stem cells located at the base of the tooth. These cells offer an excellent model to study dental stem cells.

The researchers developed a method to record the division, movement, and specification of these cells. By tracing the descendants of genetically labeled cells, they also showed that Sox2 positive stem cells give rise to enamel-forming ameloblasts as well as other cell lineages of the tooth.

– Although human teeth don’t grow continuously, the mechanisms that control and regulate their growth are similar as in mouse teeth…

 

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