This encouraged Khandelwal to search for the PS gene in the genomes of plants including the recently sequenced moss (Physcomitrella patens) genome, for which the Quatrano lab had access. In addition to the known Arabidopsis presenilin, she found the gene in Physcomitrella and asked, What is PS doing in moss" Is it acting as an enzyme or does it have a different function"
Forming a collaboration
Moss, like yeast, has this great ability where you can actually select a gene and remove it, mutate it, or replace it with another gene from any source. This approach is how we begin to discern a genes value and function in moss, said Quatrano, who was a world leader in getting the moss genome sequenced. It is an excellent system to experimentally discern gene function because of this property as well as others that we and a worldwide consortium have developed over the last several years.
Thus, collaboration was born. By engaging the expertise of the team in the Kopan lab, the Quatrano lab proceeded to start experimenting with PS in moss, which finally resulted in a fruitful combined project, the results of which was recently reported in the Proceedings of the National Academy of Science. Khandelwal proceeded to remove presenilin, and the result was an obvious change- a phenotype. Moss lacking presenilin looked different, growing with straight, rigid filaments instead of curved and bent filaments like the parent moss with the presenilin gene intact.
That showed the gene has an obvious function that obviously, did not require Notch. We just dont know exactly what it is yet, but we have proposed a hypothesis to be tested, Quatrano said.
The phenotype piq
|Contact: Tony Fitzpatrick|
Washington University in St. Louis