L4440 vector (V012784)

Price Information

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V012784 L4440 In stock (lyophilized plasmid)

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Two vials of lyophilized plasmid will be delivered, each vial is about 5µg.

Basic Vector Information

E. coli bacteria carrying RNAi plasmids that produce the desired dsRNA can be fed to worms, and the dsRNA is transferred to the worm via the intestinal tract. RNAi plasmids typically consist of DNA coding sequence from the intended target gene cloned between two T7lac promoters. The plasmid also has a selectable marker that confers resistance to an antibiotic, in this case ampicillin. In 7.15, you will use the E. coli strain HT115 carrying various L4440 plasmids, each containing a different cloned gene sequence. HT115 is an RNase III-deficient E. coli strain with IPTG-inducible T7 polymerase activity. To induce dsRNA production from these plasmids, the HT115 bacteria is grown on special RNAi NGM feeding plates that contain IPTG and the ampicillin analog carbenicillin. Carbenicillin is preferred over ampicillin because it tends to be more stable.

      • Vector Name:
      • L4440
      • Antibiotic Resistance:
      • Ampicillin
      • Length:
      • 2790 bp
      • Type:
      • RNAi
      • Source/Author:
      • Andrew Fire
      • Copy Number:
      • High copy number
      • Promoter:
      • T7
      • Cloning Method:
      • Enzyme Cut
      • Growth Strain(s):
      • stbl3
      • Growth Temperature:
      • 37℃
      • Expression Method:
      • IPTG induced

L4440 vector Vector Map

L44402790 bp600120018002400T7 promoterSK primerKS primerT7 promoterM13 fwdf1 oriAmpR promoterAmpRori

Plasmid Resuspension Protocol:

1. Centrifuge at 5,000×g for 5 min.

2. Carefully open the tube and add 20 μl of sterile water to dissolve the DNA.

3. Close the tube and incubate for 10 minutes at room temperature.

4. Briefly vortex the tube and then do a quick spin to concentrate the liquid at the bottom. Speed is less than 5000×g.

5.Store the plasmid at -20 ℃.


  • Chen HH, Dewer Y, Wang Y, Tan SQ, Liu XL, Shi WP. Interference with orco gene expression affects host recognition in Diorhabda tarsalis. Front Physiol. 2022 Dec 20;13:1069391. doi: 10.3389/fphys.2022.1069391.

L4440 vector Sequence

Copy Sequence

Download GeneBank File(.gb)

LOCUS       Exported                2790 bp ds-DNA     circular SYN 23-SEP-2021
DEFINITION  synthetic circular DNA
SOURCE      synthetic DNA construct
  ORGANISM  synthetic DNA construct
REFERENCE   1  (bases 1 to 2790)
  TITLE     Direct Submission
FEATURES             Location/Qualifiers
     source          1..2790
                     /organism="synthetic DNA construct"
                     /mol_type="other DNA"
     promoter        19..37
                     /note="T7 promoter"
                     /note="promoter for bacteriophage T7 RNA polymerase"
     primer_bind     95..111
                     /note="SK primer"
                     /note="common sequencing primer, one of multiple similar 
     primer_bind     complement(181..197)
                     /note="KS primer"
                     /note="common sequencing primer, one of multiple similar 
     promoter        complement(223..241)
                     /note="T7 promoter"
                     /note="promoter for bacteriophage T7 RNA polymerase"
     primer_bind     complement(251..267)
                     /note="M13 fwd"
                     /note="common sequencing primer, one of multiple similar 
     rep_origin      409..864
                     /note="f1 ori"
                     /note="f1 bacteriophage origin of replication; arrow 
                     indicates direction of (+) strand synthesis"
     promoter        890..994
                     /note="AmpR promoter"
     CDS             995..1855
                     /note="confers resistance to ampicillin, carbenicillin, and
                     related antibiotics"
     rep_origin      2026..2614
                     /note="high-copy-number ColE1/pMB1/pBR322/pUC origin of