A exciting research paper “Control of alternative RNA splicing and gene expression by eukaryotic riboswitches” published in Nature details the mechanism of how riboswitches work in Neurospora crassa. While riboswitches have been found and studied in bacteria there has not been extensive work showing how they work in fungi. In bacteria the riboswitch acts as the direct interacting sensor that switches gene expression off through a structural change in the RNA and fit in nicely with the RNA world view.
Using N. crassa, the authors show that alternative splicing is directly regulated through the thiamine metabolism genes which contains previously identified riboswitches. As also highlighted in the accompanying commentary this is also an interesting examples of direct RNA regulation of alternative splicing rather than through peptides like SR proteins.
We got word last week from the JGI that our DNA for Neurospora tetrasperma and N. discreta have passed QC and library QC and are on their way to being sequenced. The center also plans to do some EST sequencing to improve gene calling abilities.
Why more Neurospora genomes? The sequencing proposal discussed these species as a model system for evolutionary and ecological genetics. It will allow us and others to test several hypotheses about the molecular evolution of things like genome defense in Neurospora and to understand more about the evolutionary history of the model organism N. crassa.
Continue reading More Neurospora genomes
I’m including a recapping as many of the talks as I remember. There were 6 concurrent sessions each afternoon so you have to miss a lot of talks. The conference was bursting at the seams as it was- at least 140 people had to be turned away beyond the 750 who attended.
If there was any theme in the conference it was “Hey we are all using these genome sequences we’ve been talking about getting”. I only found the overview talks that solely describe the genome solely a little dry as compared to those more focused on particular questions. I guess my genome palate is becoming refined.
Continue reading Fungal Genetics 2007 details
Self and non-self recognition is important for fungi when hyphae interact fuse if they should compartmentalize and undergo apoptosis to kill the heterokaryoton or exchange nutrients. This process is part of cell defense and to limit to the movement of mycoviruses.
A paper in PLOS ONE describes the Genesis of Fungal Non-Self Repertoire. This kind of work goes on down the hall from us as well in the Glass lab among others. This recent paper describes het genes, which contain WD40 repeats and different combinations of these help control specificity. There is of course a diverse literature on this subject especially in Neurospora, and I’m not reviewing it here, but it is an imporant process in understanding how fungi interact with their environment.
Here is an image of Neurospora crassa I took today in my first attempt at squashes. These are from strains that Dave Jacobson grew up with his constructs so I can’t take any credit other than playing with the microscope next door. Now my first attempt came out badly, so this is actually Dave’s prep as well. And these got dry so they aren’t as nices as they could be. For much nicer images, see N.B. Raju’s.
All that said, I hope these quick images give a hint at the extremely cool structures these fungi produce. These 8-chain ascospores are the result of meoisis that took place inside the perithecia (which was squeezed gently to release the rosettes [or not too gently in my case]).
( I was previous confused about the sample and had labeled this N. tetrasperma which has 4-chained ascospores [tetra] while this sample is crassa which has 8).