Cloning 7 casein gBlocks, 12Sep2014 and on

Experiment: Cloning 7 casein gBlocks into pD1214, transforming into E. coli, extracting and sequencing plasmid DNA

Overview:

• During this series of experiments, we will insert seven casein gene constructs (detailed below) into the pD1214 vector and transform our seven constructs into E. coli. We will then perform a midiprep plasmid DNA extraction, quantify our plasmid DNA, and submit all seven constructs for sequencing. Sequence-confirmed DNA is then ready to be transformed into yeast.

Casein constructs

1) P.FAKS.bovAlphaS1.S

2) P.FAKS.bovAlphaS2(Kex-).S

3) P.FAKS.bovAlphaS2(Kex+).S

4) P.FAKS.humBeta.S

5) P.FAKS.humKappa(Kex-).S

6) P.FAKS.Beta(A2).S (bov)

7) P.FAKS.bovKappa.S

• These gBlock sequences have 5' and 3' SapI sequences, followed by full length FAKS, followed by human Kappa Casein (Kex+). Electra cloning cleaves at SapI sites and ligates simultaneously.

• We cloned into pD1214. This vector was ordered from DNA2.0 and is linearized upon arrival. Our insert is treated with Electra enzyme mix which cuts and ligates our "SapI.gene.SapI" and inserts it into the pD1214 vector.

• SapI treated DNA has an ATG overhang at the 5' end and a GGT overhang at the 3' end. Our complete vector will have the alphafactorfull signal sequence, which leads into another Methionine (M), followed by the rest of the human kappa casein protein.

All you need to know about the Electra system.

Cloning casein gBlocks into pD1214 & transforming plasmids into E. coli

September 12, 2014

• Participants: Advait, Patrik, Johan, Minakishi, Rachel, Lafia, Nikola, Aaron, Wes, Arif

• Location: BioCurious

• Materials & Methods, Electra Cloning:
  • We resuspended all lyophilized IDT gBlock DNA as in DNA Handling using 0.5X TE (1X TE, pH 7.5: 1 diH2O). Final DNA concentration = 20ng/uL, per Electra cloning kit requirements.
  • Completed 8 separate reactions, one for each gBlock and one positive control using DNA supplied in the kit.
  • 5uL reaction products used immediate for transformation into E. coli, below. Remainder stored at -20°C, BioCurious freezer. Each tube labeled with date and casein construct ID.

Reaction:

1uL pD1214 (20ng)
1uL (20ng) of appropriate casein gBlock or (+) control DNA 
2uL Electra Buffer
1uL of Electra enzyme mix
15uL of Water
----
20uL, Room Temperature, 20min.

• Materials & Methods, Transforming Mix & Go Competent dH5alpha E. coli with gBlocks in pD1214, above:
  • We used the Zymo Research instruction manual for "Premade Mix & Go Competent E. coli Cells." Media:Zymo_E._coli_competent_cells_transformation_protocol.pdf‎
  • We completed 10 reactions: one for each of the 8 Electra cloning reactions, one pGLO positive control, one diH2O negative control.
    • Thawed individual tubes of Mix & Go chemically competent, dH5alpha E. coli cells slowly on ice.
    • Prewarmed LB agar plates with Carb-50, 100mm (Teknova), at 37°C.
    • Added 5uL of each casein:pD1214 or appropriate control to individual thawed tube of 100uL competent cells. Mixed gently.
    • Immediately incubated on ice for 10 min.
    • Plated 100uL of each reaction to LB carb plates, using one individualy wrapped spreader/reaction.
      • Inducible promoter for pGLO positive control requires arabinose, so 200uL of arabinose spread onto that LB carb plate prior to transformation mix being spread.
    • Incubated plates overnight at 37°C.

September 14, 2014

• Results:
  • All casein:pD1214 --> dH5alpha E. coli transformation reactions yielded colonies on LB carb EXCEPT P.FAKS.humBeta.S. Few colonies for P.FAKS.humKappa(Kex-).S, and multiple colonies on remaining successful plates,
  • Positive and negative control plates as expected.

Repeating transformation of P.FAKS.humBeta.S:pD1214 into Mix & Go competent dH5alpha E. coli

September 14, 2014

• Aims: Of the September 12, 2014 transformations (gBlocks:pD1214 to the dH5alpha strain of E. coli & controls, above), only one failed: P.FAKS.humBeta.S:pD1214. We are repeating this transformation using the Electra cloning reaction from September 12, 2014.

• Participants:

• Location: BioCurious

• Materials and Methods:
  • Repeated the transformation using Media:Zymo_E._coli_competent_cells_transformation_protocol.pdf‎ as described in Methods September 14, 2014, above, with the following changes:
    • To attempt to improve transformation efficiency, we added an outgrowth step after 10 minute incubation on ice. Incubated transformation reactions in liquid SOC media: 2.5 hours at 37°C.

September 15, 2014

• Results: No growth for P.FAKS.humBeta.S:pD1214 to dH5alpha E. coli observed on LB carb plates incubated overnight at 37°C.

• Discussion: Second unsuccessful transformation could have been due to failed 1) transformation 2) Electra cloning or 3) resuspension of IDT gBlock DNA. Ideal to quantify P.FAKS.humBeta.S IDT gBlock resuspension to confirm contains DNA, however, we don't have access to a nanodrop UV spec, and quantifying on BioCurious's Beckman Coulter DU 640 spectrophotometer likely to require more DNA than would be prudent to use (see DNA quantification on September 1, 2014: CLONE 082514 humKappaCasein(Kex+).) Failure of Electra cloning possible due to large number of experimental participants and multiple pipetting steps.

• Future Directions: We will repeat both Electra cloning and transformation for P.FAKS.humBeta.S.