*3.3. Cloning of Full-Length Cppsy cDNA and Its Corresponding Gene*

Degenerate primers (Table 1) were designed for the amplification of a partial *Cppsy* cDNA from *C. protothecoides* CS-41. The primers were derived from the highly conserved nucleotide and amino acid sequences reported for the *psy* genes from five kinds of algae (*C. reinhardtii*, *H. pluvialis*, *D. salina*, *D. bardawil*, and *Chlorella* NC\_64A). 

Sets of specific primers were synthesized based on the sequence of putative insert for 5ȝ- and 3ȝ-RACE [34]. YFO1 and YRI1 were used for 5ȝ-RACE, and YFO2 and YRI2 (Table 1) were used for 3ȝ-RACE. RACE was performed using the 5ȝ-Full RACE Kit and 3ȝ- Full RACE Core Set Version 2.0 (TaKaRa, Dalian, China) according to the manufacturer's protocol. The RACE products were gel purified and sequenced as previously described. One pair of specific primers, YF1 and YR1 (Table 1), was designed from the sequences of the 5ȝ- and 3ȝ-RACE fragments to amplify the fulllength *Cppsy* cDNA and its corresponding gene. 
