Revision as of 01:25, 31 October 2017

SynORI constitutive plasmid copy number device intermediate (0.15 Anderson)

This construct is an intermediate to full SynORI constitutive copy number device. It can be combined with part:BBa_K2259000 replication iniatiation part. It consists of an anderson promoter and ColE1 RNA I gene (without promoter).

When combined with RNA II (part:BBa_K2259057) this device sets a defined copy number for a plasmid.

Sequence and Features

Introduction

Biology

ColE1 plasmid replication overview

Figure 1. Main principles of ColE1 plasmid family replication. (Citation needed)

ColE1-type plasmid replication begins with synthesis of plasmid encoded RNA II (also called primer transcript) by RNA polymerase which initiates transcription at a site 555bp upstream of origin of replication. The RNA transcript forms a RNA - DNA hybrid with template DNA near the origin of replication. Hybridized RNA is then cleaved at the replication origin by RNAse H and serves as a primer for DNA synthesis by DNA polymerase I (Figure 1. A).

Initiation of replication can be inhibited by plasmid encoded small RNA, called RNA I . Synthesis of RNA I starts 445 bp upstream of the replication origin and proceeds in the direction opposite to that of RNA II synthesis, and terminates near the RNA II transcription initiation site. RNA I binds to RNA II and thereby prevents formation of a secondary structure of RNA II that is necessary for hybridization of RNA II to the template DNA (Figure 1. B).

For RNA I to inhibit primer formation, it must bind before the nascent RNA II transcript extends to the replication origin. Consequently, the concentration of RNA I and the rate of binding of RNA I to RNA II is critical for regulation of primer formation and thus for plasmid replication.

Interaction between RNA I and RNA II can be amplified by Rop protein, see part:BBa_K2259010.

Rop dimer is a bundle of four tightly packed alpha helices that are held by hydrophobic interactions (Fig. 2).

Usage with SynORI (Framework for multi-plasmid systems)

About SynORI

SynORI is a framework for multi-plasmid systems created by Vilnius-Lithuania 2017 which enables quick and easy workflow with multiple plasmids, while also allowing to freely pick and modulate copy number for every unique plasmid group! Read more about [http://2017.igem.org/Team:Vilnius-Lithuania SynORI here]!

Characterization

In order to characterize this construct it must be cloned next to RNA II gene. Please see part:BBa_K2259067.

References