3.3. Semi-quantitative RT-PCR analysis. Human normal adult tissue RNA samples were purchased commercially (Stratagene, La Jolla, CA, USA or Millipore Chemicon, Billerica, MA, USA). cDNA was synthesized using the GeneAmp RNA PCR kit (Applied Biosystems, Foster City, CA, USA) in combination with RNase inhibitor (Roche Applied Science, Indianapolis, IN, USA) and M-MuLV reverse transcriptase. The subsequent PCR amplification of cDNA was performed using the AmpliTaq Gold DNA Polymerase (Applied Biosystems, Foster City, CA, USA) following standardized protocols [21, 22] . The vulgate transcript APOM1 (Ensembl: ENST00000375916) and the novel transcript APOM5 were amplified using primer RT-PCR-YY12 paired with RT-PCR-YY13 and RT-PCR-YY12 paired with RT-PCR-YY14, respectively (Supplementary Table S4 ). GAPDH was amplified as a house-keeping gene control for RNA integrity and equal loading using the GAPDH primers, RT-PCR-Tao1 and RT-PCR-Tao2 [23] (Supplementary Table S1 ).