Gen CSF3 merupakan gen penyandi human granulocyte-colony stimulating factor hG-CSF. Gen CSF3 yang digunakan dalam penelitian ini merupakan gen sintetik dari penelitian terdahulu disebut CSF3syn yang dikonstruksi secara in vitro. Gen tersebut mengandung kodon preferensi Escherichia coli dan telah berhasil digunakan untuk mengekspresikan protein hG-CSF rekombinan pada E. coli menggunakan plasmid ekspresi berbasis promotor T7. Gen CSF3syn disubkloning ke dalam plasmid ekspresi yang mengandung promotor rhaBAD pada penelitian ini. Promotor ini dapat terinduksi oleh rhamnose dalam media sebagai sumber karbon. Tujuan penelitian ini adalah mendapatkan konstruk plasmid rekombinan pJ804-mCSF3 sebagai sumber vektor alternatif untuk produksi protein hG-CSF rekombinan pada sistem ekspresi E. coli menggunakan plasmid berbasis promotor rhaBAD. Konstruksi plasmid dilakukan melalui subkloning gen CSF3syn ke dalam plasmid pJ804. Terdapat dua varian gen CSF3syn yang digunakan, yaitu mCSF3-ori dan mCSF3-new2. Kedua gen tersebut diisolasi masing-masing dari plasmid pJ414-mCSF3-ori dan pJ414-mCSF3-new2 setelah didigesti dengan enzim restriksi NdeI dan XhoI. Gen target dan plasmid selanjutnya diligasi dan plasmid rekombinan yang diperoleh diklon ke dalam E. coli DH5?. Sebanyak 12 dari 30 koloni transforman pJ804-mCSF3-ori dan 7 dari 44 koloni transforman pJ804-mCSF-new2, positif menunjukkan pita gen CSF3syn sebesar 558 pb setelah diverifikasi menggunakan teknik PCR koloni dan PCR plasmid. Analisis digesti plasmid menggunakan enzim NdeI dan XhoI mengonfirmasi situs ligasi dan ukuran dari plasmid rekombinan yang diperoleh 4.723 pb. Plasmid rekombinan pJ804-mCSF-ori dan pJ804-mCSF3-new2 telah berhasil dikonstruksi.

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CSF3 is a gene that encodes the human granulocyte colony stimulating factor hG CSF. The CSF3 gene used in this study was a synthetic gene from a previous study called CSFsyn that was constructed in vitro. The gene contains the Escherichia coli codon preference and has been successfully used to express the recombinant hG CSF protein in E. coli using T7 promoter based expression plasmid. The CSF3syn gene was subcloned into an expression plasmid containing rhaBAD promoter in this study. This promoter can be induced by rhamnose in the media as a carbon source. The purpose of this study was to obtain a recombinant plasmid construct of pJ804 mCSF3 as an alternative vector source for the production of recombinant hG CSF protein in an E. coli expression system using rhaBAD promoter based plasmid. The plasmid construction was performed by subcloning the CSF3syn gene into the pJ804 plasmid. There are two variants of CSF3syn genes used, mCSF3 ori and mCSF3 new2. The two genes were isolated from pJ414 mCSF3 ori and pJ414 mCSF3 new2 plasmids respectively after digestion using NdeI and XhoI restriction enzymes. The target genes and plasmid were subsequently ligated and recombinant plasmid obtained were cloned into E. coli DH5 . Twelve out of the 30 transformant colonies of pJ804 mCSF3 ori and 7 out of 44 transformant colonies pJ804 mCSF new2, positively demonstrated the presence of CSF3syn gene band of 558 bp. Those colonies have been verified using colony PCR and plasmid PCR techniques. Plasmid digestion analysis using NdeI and XhoI enzymes confirmed ligation site and size of the recombinant plasmids obtained 4.723 bp. Recombinant plasmids pJ804 mCSF ori and pJ804 mCSF3 new2 have been successfully constructed.