Team:Fudan/Basic Parts

2018 iGEM Team:Fudan - Basic parts

Basic parts

 

Basic parts

 

BBa_K2549006 mouse Notch 1 core

Our favorite basic part for this year’s iGEM competition is mouse Notch 1 receptor’s core domain.
006 screencapture

Notch core consists of the negatively regulated region and transmembrane region of the mouse Notch 1 receptor. It is the joint that empowers SynNotch the high modularity and proper activation. From the N terminal to C terminal, it is composed of three lin12-repeats (LNR) domains LNR-A, LNR-B, LNR-C, the heterodimerization domain (HD), and the transmembrane domain. The LNR-AB linker between LNR-A and B is like a plug that occludes ADAM from cleaving wild type extracellular domain can be substituted by antiGFP scFvs like LaG16 and anti-CD19, while its intracellular domain can be replaced by specialized transcription factors. Notch core is also the key to the activation of both wild type Notch receptors and SynNotch.

Structure of the negative regulatory region of Notch 1 receptor, surface delivery, and optimization.
a-c. Shows structure of the Notch 1 core, with more detail on the NRR. (With structural information adapted from Gordon et al., 2009)
d. Shows that mouse SynNotch with LaG16-2 scFv (single chain fragment variants) as ectodomain is expressed on the 293T cell membrane as an example via anti-myc AF488 immunofluorescence staining. Shown here the light parts.
e. A conclusive diagram of our Notch optimization. We have 5 mutations that exhibit better activation performance to SynNotch with LaG17 as scFv.

SynNotch Class ARFaS*) Preferred
LaG17-mN1c-tTAA II 1.67 ± 0.20
LaG17-6G-LNRA[-]mN1c-tTAA I 1.73 ± 0.29 ☆
LaG17-LNRA cbs(D1433K)mN1c-tTAA II 2.69 ± 0.11 ☆
LaG17-LNRA cbs(D1433Q)mN1c-tTAA II Needs more repeat
LaG17-LNRAlnkr(L1457V)mN1c-tTAA I 2.12 ± 0.39 ☆
LaG17-LNRAlnkr(L1457G)mN1c-tTAA II 2.55± 0.55

*) ARFaS: activation ratio fold of activating-form SynNotch

See more in Optimization

It is suggested by recent research that Notch activation begin as the receptor is first "opened up" at its negatively regulatory region (NRR) by the mechanical force exerted by Notch-bound ligand endocytosis on signal-sender cell, exposing its cleavage sites to proteases. Intracellular proteolytic action releases the Notch intracellular domain (NICD). In the majority of cellular interactions, the free Notch intracellular domain then translocate into the cell nucleus via nuclear localization sequence to regulate downstream signaling. For wild type Notch, the Notch intracellular domain would interacted with its major downstream effector CBF-1/Suppressor of Hairless/Lag-1 (CSL) on their target DNA. Together they recruit co-factors to activate endogenous downstream transcription. For SynNotch, specialized transcription factors will exclusively participate in regulation of genetic circuits that allow user-defined cellular responses.

2018 team Fudan abstract

Abstract

Contact-dependent signaling is critical for multicellular biological events, yet customizing contact-dependent signal transduction between cells remains challenging. Here we have developed the ENABLE toolbox, a complete set of transmembrane binary logic gates. Each gate consists of 3 layers: Receptor, Amplifier, and Combiner. We first optimized synthetic Notch receptors to enable cells to respond to different signals across the membrane reliably. These signals, individually amplified intracellularly by transcription, are further combined for computing. Our engineered zinc finger-based transcription factors perform binary computation and output designed products. In summary, we have combined spatially different signals in mammalian cells, and revealed new potentials for biological oscillators, tissue engineering, cancer treatments, bio-computing, etc. ENABLE is a toolbox for constructing contact-dependent signaling networks in mammals. The 3-layer design principle underlying ENABLE empowers any future development of transmembrane logic circuits, thus contributes a foundational advance to Synthetic Biology.