Preprint Article Version 3 This version is not peer-reviewed

The Meaning of the Microprocessor: Accounting for Evolution of Structural-Functional Novelty in the Canonical microRNA Biogenesis Pathway

Version 1 : Received: 19 April 2019 / Approved: 23 April 2019 / Online: 23 April 2019 (11:06:29 CEST)
Version 2 : Received: 23 April 2019 / Approved: 24 April 2019 / Online: 24 April 2019 (12:20:07 CEST)
Version 3 : Received: 20 September 2019 / Approved: 23 September 2019 / Online: 23 September 2019 (10:16:40 CEST)

How to cite: Robinson, J. The Meaning of the Microprocessor: Accounting for Evolution of Structural-Functional Novelty in the Canonical microRNA Biogenesis Pathway. Preprints 2019, 2019040254 (doi: 10.20944/preprints201904.0254.v3). Robinson, J. The Meaning of the Microprocessor: Accounting for Evolution of Structural-Functional Novelty in the Canonical microRNA Biogenesis Pathway. Preprints 2019, 2019040254 (doi: 10.20944/preprints201904.0254.v3).

Abstract

It is standard to identify and compare predicted protein sequence of the Drosha and Pasha genes subsidiary to detection and identification of novel microRNAs in newly sequenced taxa or review of previous deep sequencing data. Drosha and Pasha proteins are the key, conserved members of the ‘microprocessor’ protein complex which facilitates nuclear nuclear localized, pri to pre miRNA processing miRNAs of the canonical eumetazoan complement. Because of the necessity of the microprocessor for production of c anonical eumetazoan miRNA, the detection of both (1) bona fide microRNAs and (2) presence of Drosha/Pasha orthologs (or homologs) is often presented as sufficient to represent a functional canonical eumetazoan microRNA biogenesis pathway. However, the fun ctional role of the Drosha and Pasha homologs sometimes, though not always experimentally validated in non model taxa. Differentiation of ‘bona fide miRNAs’, opposed to ‘non bona fide’ small RNAs of similar size, are also necessary for miRNA identificatio n projects. Recent rubrics are based on structural and sequence elements of the miRNAs themselves, however these inclusion criteria include paraphyletic groupings of miRNAs, for example eumetazoan miRNAs and S treptophyte (green plant) miRNAs which are not produced by the Drosha/Pasha microprocessor mechanism. Therefore, a dichotomy exists between the structural definitions for miRNAs and understanding of the evolutionarily conserved function of the microprocessor and its components. In this article, I re view literature in the context of this topic and discuss philosophical significance for understanding the importance of the microprocessor in understanding the evolutionary and molecular origins of miRNA.

Subject Areas

Microprocessor, miRNA, Drosha, Pasha, miRNA biogenesis pathway, Holozoa, Metazoa, RNA interference, bona fide miRNA, canonical eumetazoan miRNA

Comments (1)

Comment 1
Received: 23 September 2019
Commenter: Jeffrey Robinson
Commenter's Conflict of Interests: Author
Comment: New text, figures.
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