Is MPSS like microarray expression analysis systems, with a hybridization-based query of an mRNA population?
Actually, it’s unlike either the oligo or cDNA microarrays. If you’re familiar with SAGE, it’s a very similar concept, but the signatures are longer (17-20 bp) and we obtain many more of them (more than a million signatures per library). The cost is high, so it’s expensive to analyze many timepoints or treatments. Solexa is presently working to bring this cost down to more reasonable levels (contact them for cost details). There is quite a bit of research value in the first few libraries for genome annotation, given that the expression levels are extremely precisely determined and the sequence of the signature is associated with this expression level information. Because such large numbers of signatures are sequenced, you can also find genes expressed at extremely low levels that may never show up in an EST library or be detectable on a microarray. Genes discovered using MPSS may be analyzed using other methods (quantitative PCR, microarrays, etc.) under a range of different conditions
