Tag Archives: RACE

5’/3′ RACE PCRs – Nested PCRs for COX2 Sequence

Due to the failure of the primary PCR on both 5′ and 3′ RACE cDNA libraries (from 20080619) yesterday, will perform nested PCR using a nested GSP designed by Steven (CgPGSRACEsrNGSP1; SR ID:1209). The 5uL of PCR reactions that were set aside yesterday were diluted to 250uL with tricine-EDTA (supplied with the Clontech SMARTer RACE cDNA Amplification Kit) as instructed in the Clontech manual. The master mix and tube layouts were exactly the same as yesterday’s, but instead of using 2.5uL of RACE cDNA library as template, I used 5uL of the diluted PCR reaction. Additionally, Universal Nested Primers were used instead of the Universal Primer Mix (both supplied in the kit). Cycling parameters followed “Program 2″ from the Clontech manual for 25 cycles.

Entire PCR rxns were run on a 1.2% gel, as instructed by the Clontech manual.

Results:

So….. What we see here is a melted gel!

But! We also see a successful PCR! The first three lanes (excluding the Hyperladder I) are 5′ RACE rxn, followed by two different negative controls (the negative control in the last lane is the one we’re really concerned with and it’s totally clean). The next three lanes are the 3′ RACE rxn, followed by two different negative controls (the negative control in the last lane is the one we’re really concerned with and it’s totally clean). As hoped/expected, we got a nice, clear product in the 5′ RACE rxn.

The bright band (~1500bp) in the 5′ RACE rxn PCR was excised and purified using Millipore Ultrafree DA columns according to protocol. Will clone and sequence this product.

5’/3′ RACE PCRs – COX2 Sequence on 5′ & 3′ RACE Libraries (from 20080619)

Ran PCRs on both the 5′ & 3′ RACE libraries created 20080619 with a new COX2 gene-specifc (GSP) primer designed by Steven (CgPGSRACEsrGSP1; SR ID: 1208). Although this primer was designed to obtain additional 5′ sequence, it was used with both 5′ and 3′ libraries as a precaution in case it accidentally designed on the wrong strand. PCR rxn was set up according to the Clontech SMARTer RACE cDNA Amplification Kit. Master mix calcs are here. PCR cycling followed “Program 1″ from the Clontech manual for 25 cycles.

After PCR completion, 5uL were transferred to a clean tube and saved, in case this PCR didn’t work and a nested PCR would need to be performed. This is according to the Clontech protocol. Samples were run on a 1.2% agarose gel, as instructed in the Clontech manual.

Results:

No bands of any kind in any sample, including the negative controls (gel not shown). Will perform nested PCR on both libraries in hopes of getting bands.

3’RACE – C.gigas 3’RACE for COX2

Used Cg_COX2_3’RACE_short (SR ID: 1197) & Cg_COX2_3’RACE_long (SR ID: 1196) and the Clonetech SMART RACE cDNA Amplification Kit (unknown acquisition date) to attempt to acquire more 3′ sequence of the C.gigas COX2 isoform. Used Gigas 3’RACE cDNA (from 20080610).

Results:

Gel Loading:

Lane 1: Hyperladder 1

Lane 2: empty

Lane 3: Cg_COX2_3’RACE_long

Lane 4: Cg_COX2_3’RACE_long NTC

Lane 5: empty

Lane 6: Cg_COX2_3’RACE_short

Lane 7: Cg_COX2_3’RACE_short NTC

Lane 8: Hyperladder 1

No products produced. This could be due to a large number of factors. The age of the cDNA (from 20080610) is well beyond what the Clontech manual says for storage term (6 months). Additionally, the Clontech polymerase used was nearly 6 years old. The kit (and its components) are of an unknown age and could factor in to the failure of this procedure. Also, the primers that were designed had less than ideal Tm, per the kit’s recommendations.

May need to sequence some previously purified potential COX2 fragments in order to obtain a more useable region of the gene for RACE.