Production and bioactivity test of recombinant protein common carp growth hormone

Abstract

This study aimed to produce recombinant growth hormone (rGH) protein of common carp (Cyprinus carpio) and evaluate its bioactivity. DNA fragment encoding mature GH protein of common carp (mCcGH) was amplified by polymerase chain reaction (PCR) method and PCR products were then ligated into pCold I to generate pCold I-mCcGH protein expression vector. Escherichia coli BL21 (DE3) harboring pCold I-mCcGH was cultured in the 2xYT medium at 15 °C for 24 hours and protein production was induced by isopropyl-beta-thio galactopyranoside (IPTG). The inclusion bodies containing rGH protein from E. coli transformants were isolated by sonication method and analyzed by SDS-PAGE. The result showed that rGH with molecular weight of about 25 kDa was obtained. Common carp juveniles with average body weight of 5.2±0.4 g were intramuscularly injected once a week for 4 weeks with rGH protein solution from 1 μg bacterial cells per gram fish body weight. The result showed that juveniles fish injected with rGH grew 106.56% higher than control. This result indicated that rGH produced in E. coli BL21 possessed biological activity and it may be useful to improve growth of aquaculture species.

Key words: growth hormone, recombinant protein, common carp

ABSTRAK

Penelitian ini bertujuan menghasilkan protein rekombinan hormon pertumbuhan (growth hormone, GH) dari ikan mas (Cyprinus carpio) dan menguji bioaktivitasnya. Fragmen DNA penyandi protein matang (mature) GH ikan mas (mCcGH) diamplifikasi dengan menggunakan metode PCR dan hasilnya kemudian diligasi ke dalam pCold-I untuk menghasilkan konstruksi vektor ekspresi pCold-I-mCcGH. Plasmid pCold-I-mCcGH ditransformasi ke bakteri Escherichia coli BL21 (DE3), dikultur dalam media 2xYT cair pada suhu 15°C selama 24 jam dan produksi protein diinduksi dengan menggunakan isopropyl-beta-thio galactopyranoside (IPTG). Badan inklusi yang mengandung protein rekombinan GH (rGH) dari bakteri E. coli transforman diisolasi menggunakan metode sonikasi dan dianalisis dengan menggunakan SDS-PAGE. Hasil penelitian menunjukkan bahwa rGH dengan bobot molekul sekitar 25 kDa berhasil diproduksi. Benih ikan mas dengan bobot rata-rata 5,15±0,4 g diinjeksi secara intramuskular satu kali per minggu selama 4 minggu dengan larutan rGH hasil ekstraksi dari 1 µg pelet bakteri/g bobot ikan. Benih yang disuntik dengan rGH tumbuh sekitar 100% lebih cepat bila dibandingkan dengan kontrol yang tidak diinjeksi rGH. Hasil ini mengindikasikan bahwa rGH yang diproduksi dalam bakteri E. coli memiliki bioaktivitas dan dapat bermanfaat untuk memacu pertumbuhan spesies ikan-ikan budidaya.

Kata kunci: hormon pertumbuhan, protein rekombinan, ikan mas