Hi all,
Please I'm having some very serious problems on my project. What I am trying to do is to:
1. extract an EGFP gene from pSAT1-EGFP-C1 (4553 bp) and clone it onto the binary vector, pPZP-RCS2-ocs-bar-R1 (8637 bp)and then transform it with competent cells.
2. Later on, I will use it to clone some genes from tomato plants by silencing usin VIGS.
But the problem I am having now is in the first step. I havn't been able to clone the EGFP gene onto the binary vector. The protocol I have been using is:
For the vector
(a) plasmid extraction of vector (plasmid conc. is usually high)
(b) enzyme digestion of vector with Asc1 enzyme (I get one band after cutting)
© agarose gel purification of vector
(d) measurement of vector DNA concentration using nanodrop (sometimes I get low conc.)
For the insert
(a) plasmid extraction of insert (plasmid conc. is usually high)
(b) enzyme digestion of insert also with Asc1 enzyme (I get 2 bands after cutting, then I use the lower band, with size of like 1600bp, for gel purification)
© agarose gel purification of insert
(d) measurement of insert DNA conc. (also I get very low conc. of DNA)
Then I go ahead with ligation of the vector and insert by adding 4ul of insert to 1ul or 2ul of vector; 1ul of T4 DNA ligase; 1ul of T4 DNA ligase buffer; and add up with ddH2O in a 10ul reaction and incubate @ 16oC overnight.
After that, I then go ahead with transformation using competent cells that were ordered and tested. I grow the ligation mix on spectinomycin selective media since the vector has spectinomycin resistance for 16 hours. But at the end, I will either: not see any growth; or see some king of very tiny colonies that won't grow on LB media.
Please, I really need the help of this forum to know what the prob is. I have been stuck here for several months now. I will really appreciate all kinds of opinions on this.