Efektivitas Promoter Keratin, Heat Shock, dan β-Aktin pada Transgenesis Ikan Nila (Oreochromis niloticus)

Abstract

Salah satu pertimbangan penting dalam produksi ikan transgenik adalah pemilihan promoter; sekuen DNA yang terletak di bagian upstream suatu gen yang akan mengatur tempat, waktu dan tingkat ekspresi suatu gen yang berhubungan dengan suatu karakter. Begitu penting perannya, sehingga promoter dianalogikan sebagai switch suatu gen dan menjadi salah satu faktor penentu keberhasilan transgenesis.

One of important consideration in production of fish transgenic is the choice of promoter for regulating the expression of a foreign gene. In this study, effectiveness of four promoters was examined in transgenic Nile tilapia. Japanese Flounder Keratin (pjfKer), Heat shock (prtHsc), medaka β-actin (pmBA) and tilapia β-actin (ptiBA) promoters were linked to green fluorescent protein (GFP) as a reporter gene to compare activity of promoters. The aim of the research is to evaluate effectiveness of four promoters on Nile tilapia transgenesis. Promoters used in this research are keratin, heat shock, and β- actin linked with GFP gene as marker. Gene transfer method used microinjection with concentration of gene construct 50 µg/ml and injected at one cell phase of embryo. Effectiveness of promoter was determined by percentage of embryos expressing GFP, pattern and level of GFP expression. Based on the expression pattern, keratin was fastest in expressing GFP gene compared to three other promoters. Keratin and heat shock promoters showed similarly high percentage of embryo expressing GFP (55%). Both of promoters also showed similarly high expression level (218 ng and 192 ng, respectively) compared to others (50 ng on ptiBA). Keratin and heat shock was similarly more effective compare to medaka β-actin and tilapia β-actin.