solation of Full-Length Dlk-1 cDNA from Human. PCR primers were designed based on the gene sequences of human Dlk-1 (GenBank accession no. U15979). Sequences of the prepared primers were as follows: forward primer: 5′-cgc-gtc-cgc-aac-cag-aag-ccc-3′ and reverse primer: 5′-aag-ctt-gat-ctc-ctc-gtc-gcc-ggc-c-3′. To the reverse primer, HindIII restriction site was added. PCR was performed using these primers and cDNAs synthesized from total RNAs prepared from human liver at embryonic week 10 (TaKaRa). PCR product was cloned into PCRII vector (Invitrogen) (pCRII-hdlk-1). To construct the expression vector, Flag tag sequences were inserted into the HindIII/SalI site of pBluescript II SK(+) vector (Stratagene) (pBS-Flag). Then, an EcoRI/HindIII fragment was cleaved off from pCRII-hdlk-1 and inserted into the EcoRI/HindIII site of pBS-Flag vector (pBS-hdlk-1-Flag). An EcoRI/SalI fragment was cleaved off from pBS-hdlk-1-Flag and inserted into the EcoRI/XhoI site of pcDNA3.1 vector (Invitrogen) (pcDNA-hdlk-1-Flag).