Transcriptome profiling: methods and applications-A review

Global transcriptional profiling is a powerful tool that can expose expression patterns to define cellular states or to identify genes with similar expression patterns. In recent years, transcriptome profiling has been widely used to understand the genetic regulation of a particular cell type. Transcriptome is defined as a full range of messenger Ribonucleic acid (RNA) molecule expressed by an organism. In other words a transcriptome represents the small percentage of genetic code that is transcribed into RNA molecules. It can offer valuable information on the significant biological processes behind the maintenance of the functionality of the cell. Transcriptomics provides fundaments for more definitively designed studies and guidance to select the genes for functional studies. The technology for the study of the transcriptome is not dependent on any prior knowledge of the genes expressed in the cells. However, with regards to the administration and interpretation of the enormous data provided by transcriptome profiling challenges remain. Four methods have been reviewed here that is, Micro array technology, Serial Analysis of Gene Expression (SAGE), RNA sequencing (RNA-Seq) and Massively Parallel Signature Sequencing (MPSS). The use of these technologies to analyse the expressed transcripts in several prokaryotic and eukaryotic genomes has revealed the high complexity of transcriptomes.