Part:BBa_K3815011

Part of the V-ATPaseB gene of Frankliniella occidentalis to synthesize dsRNA for RNAi
This is a section of V-ATPaseB gene of Frankliniella occidentalis to synthesize dsRNA for RNAi. To product dsRNA, this sequence is inserted in L4440 plasmid, and transformed into HT115(DE3).

purpose

vATPase-B is a gene that encodes a protein that is part of a subunit of vATPase, a type of ATP-dependent proton pump that regulates the pH of various cell organelles. Since this gene is essential for thrips, knockdown of vATPase-B results in the death of the thrips Frankliniella occidentalis.[1]

Usage and Biology

RNAi
RNAi (RNA interference) is a process in which externally introduced dsRNA suppresses the expression of genes that have complementary sequences to the dsRNA.

L4440
L4440 is a plasmid vector having two convergent T7 promoters adjacent to the multi-cloning site. By inserting a portion of the target gene sequence into the multi-cloning site of this plasmid, the target sequence is transcribed from both sides, and dsRNA can be obtained when both parts anneal.

HT115(DE3)
HT115 (DE3) is an RNase III-deficient E. coli strain that has been modified to express T7 RNA polymerase from an IPTG-inducible promoter. It lacks dsRNA-specific RNase III, which allows it to produce high levels of specific dsRNA. These attributes allow HT115 (DE3) to be a promising strain for the preparation of large amounts of viral dsRNA in vivo.

Sequence and features

Assembly Compatibility:

• 10
  COMPATIBLE WITH RFC[10]
• 12
  COMPATIBLE WITH RFC[12]
• 21
  INCOMPATIBLE WITH RFC[21]

  Illegal BglII site found at 452
  
• 23
  COMPATIBLE WITH RFC[23]
• 25
  COMPATIBLE WITH RFC[25]
• 1000
  INCOMPATIBLE WITH RFC[1000]

  Illegal BsaI site found at 320
  

cloning

This part was inserted in L4440. The L4440 has two t7 promoters, and this ​part are transcribed from both sides.

production and purification methods

Fig1.1.L4440 2 vATPase-B (total 7ug nucleotic acid were loaded) 3 vATPase-B (total 1ug nucleotic acid were loaded)
700bp band is target RNA

We produced dsRNA and purify this [2].
The 1L LB culture was started at 37°C and IPTG (final 0.2mM) was added when OD exceeded 0.4 to induce RNA production for 4 hours.
E. coli was disrupted and precipitated with NaCl, and RNA contained in the supernatant was purificated by phenol-chloroform treatment.

Electrophoresis in acrylamide gel was performed to confirm whether the target RNA was produced.

We could confirm RNA production.

Reference

1 Andongma, A.A., Greig, C., Dyson, P.J., Flynn, N., and Whitten, M.M.A. (2020). Optimization of dietary RNA interference delivery to western flower thrips Frankliniella occidentalis and onion thrips Thrips tabaci. Arch. Insect Biochem. Physiol. 103, e21645.

2 Papić, L., Rivas, J., Toledo, S., and Romero, J. (2018). Double-stranded RNA production and the kinetics of recombinant Escherichia coli HT115 in fed-batch culture. Biotechnol Rep (Amst) 20, e00292.