TRAMP complex

TRAMP complex (Trf4/Air2/Mtr4p Polyadenylation complex) is a multiprotein, heterotrimeric complex having distributive polyadenylation activity and identifies wide varieties of RNAs produced by polymerases.It was originally discovered in Saccharomyces cerevisiae by LaCava et al., Vanacova et al. and Wyers et al. in 2005.

It interacts with the exosome complex in the nucleus of eukaryotic cells and is involved in the 3' end processing and degradation of ribosomal RNA and snoRNAs. The TRAMP complex trims the poly(A) tails of RNAs destined for Rrp6 and the core exosome down to 4-5 adenosines assisting in transcript recognition and exosome complex activation. The substrate specificity of exosomes is improved in the presence of TRAMP complex as it acts as a crucial cofactor and helps in maintaining various activities.

In this way, TRAMP plays a critical role in ridding the cell of noncoding transcripts generated through pervasive RNA polymerase II transcription, as well as functioning in the biogenesis and turnover of functional coding and noncoding RNAs.

TRAMP complex also affects various other RNA processes either directly or indirectly. It is involved in RNA export, Splicing, hetero-chromatic gene silencing and helps in maintaining stability of genome.

Pol(A) Polymerases showed various genetic interactions with DNA Topoisomerases Top1p and hence they were called topoisomerase-related function Trf4p and Trf5p due to this interaction with DNA it has an important part in genomic stability. In the cell Trf4p is in higher concentration as compared to Trf5p and also has a stronger effect on the phenotype. Trf4p is present throughout the nucleus while Trf5p is mainly found mainly in nucleolus. The Trf4p structure consists of a central domain and a catalytic domain which is similar to the structure of canonical polymerases.

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