Help! What is MPSS and where do I get started?
‘MPSS’ stands for massively parallel signature sequencing; it’s an experimental technique that quantitatively measures gene expression. mRNA is extracted from a particular tissue, and via some non-conventional cloning and sequencing steps, a short “signature” of 17-20 bp is derived from each mRNA molecule. The signatures are unique enough to assign nearly all of them to specific genes, and the total number of occurences of a given signature in a library is a measure of how highly expressed a given gene is. If 2 million signatures are sequenced in a library, distinct signatures representing the transcripts for subunits of rubisco, for example, may be sequenced hundreds of thousands of times. The signature abundance is a quantitative measurement of the expression level of those genes. Because of the methodology, signatures are immediately adjacent to the 3′ end of the 3′-most Sau3A restriction site (GATC) in cDNA sequences. There are several publications that describe the method (see the
