ISOLASI DAN KARAKTERISASI PROMOTER β-ACTIN DARI IKAN KERAPU BEBEK (Cromileptes altivelis)
Abstract
Promoter sebagai regulator ekspresi gen merupakan salah satu faktor yang mempengaruhi keberhasilan transgenesis. Penelitian isolasi dan karakterisasi promoter β-actin (ktBA) dari ikan kerapu bebek (Cromileptes altivelis) dalam rangka pembuatan ikan kerapu autotransgenik telah dilakukan. Promoter β-actin memiliki aktivitas tinggi pada jaringan otot. Sekuens promoter ktBA diisolasi menggunakan metode degenerate PCR. Sekuensing dilakukan menggunakan mesin ABI PRISM 3100. Analisis sekuens menggunakan software BLAST, GENETYX versi 7 dan TFBind. Fragment DNA hasil amplifikasi PCR yang dipotong dari vektor kloning selanjutnya diligasi dengan pEGFPN1 untuk membuat konstruksi pktBA-EGFP. Konstruksi pktBA-EGFP dimikroinjeksi ke embrio ikan zebra (Danio rerio) fase 1 sel untuk menguji aktivitas promoter ktBA. Ekspresi gen EGFP diamati menggunakan mikroskop fluoresens. Analisis sekuens menunjukkan bahwa panjang fragmen DNA hasil amplifikasi PCR sekitar 1,6 kb dan memiliki faktor transkripsi yang conserved pada promoter β-actin, yaitu CCAAT, CArG dan boks TATA. Selanjutnya, sekuens ktBA dalam konstruksi pktBA-EGFP mampu mengendalikan ekspresi gen EGFP pada jaringan otot embrio ikan zebra yang dimikroinjeksi dengan konstruksi tersebut. Dengan demikian dapat disimpulkan bahwa fragmen DNA hasil amplifikasi PCR tersebut merupakan sekuens promoter β-actin ikan kerapu bebek. Pembuatan ikan kerapu autotransgenik selanjutnya dapat dilakukan dengan mengganti gen EGFP pada pktBA-EGFP dengan gen-gen asal ikan kerapu yang mengkodekan karakter penting dalam budi daya ikan.
Promoter as gene expression regulator is one of the factors affecting the successful of transgenesis. Isolation and characterization of β -actin promoter (ktBA) from humpback grouper (Cromileptes altivelis) towards generation of autotransgenic grouper have been conducted. β -actin promoter has high activity in muscle. Sequence of ktBA promoter was isolated by using degenerate PCR method. Sequencing was performed using ABI PRISM 3100 machine. Analysis of sequences was conducted using BLAST, GENETYX version 7 and TFBind softwares. DNA fragment of PCR amplification product digested from the vector cloning was then ligated with pEGFPN1 to generate pktBA-GFP construct. The construct was microinjected into one-cell stage of zebrafish (Danio rerio) embryos to test the ktBA promoter activity. EGFP gene expression was observed by fluorescence microscope. The result of sequence analysis showed that the length of DNA fragment obtained is about 1.6 kb and containing the evolutionary conserved sequences of transcription factor for β -actin promoter including CCAAT, CArG and TATA boxes. Furthermore, ktBA sequence in pktBA-EGFP construct could drove GFP expression in muscle of zebrafish embryos injected with the construct. The results suggested that PCR amplification product is the regulator sequence of humpback grouper β -actin gene. Autotransgenic grouper can be then produced by changing GFP gene fragment of pktBA-EGFP construct with genes from grouper encoding important traits in aquaculture.
Promoter as gene expression regulator is one of the factors affecting the successful of transgenesis. Isolation and characterization of β -actin promoter (ktBA) from humpback grouper (Cromileptes altivelis) towards generation of autotransgenic grouper have been conducted. β -actin promoter has high activity in muscle. Sequence of ktBA promoter was isolated by using degenerate PCR method. Sequencing was performed using ABI PRISM 3100 machine. Analysis of sequences was conducted using BLAST, GENETYX version 7 and TFBind softwares. DNA fragment of PCR amplification product digested from the vector cloning was then ligated with pEGFPN1 to generate pktBA-GFP construct. The construct was microinjected into one-cell stage of zebrafish (Danio rerio) embryos to test the ktBA promoter activity. EGFP gene expression was observed by fluorescence microscope. The result of sequence analysis showed that the length of DNA fragment obtained is about 1.6 kb and containing the evolutionary conserved sequences of transcription factor for β -actin promoter including CCAAT, CArG and TATA boxes. Furthermore, ktBA sequence in pktBA-EGFP construct could drove GFP expression in muscle of zebrafish embryos injected with the construct. The results suggested that PCR amplification product is the regulator sequence of humpback grouper β -actin gene. Autotransgenic grouper can be then produced by changing GFP gene fragment of pktBA-EGFP construct with genes from grouper encoding important traits in aquaculture.
Keywords
cloning; β -actin promoter; autotransgenic; EGFP; Cromileptes altivelis; Danio rerio
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PDFDOI: http://dx.doi.org/10.15578/jra.2.2.2007.199-210
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