RESUMO
A beta actin cDNA of Tanichthys albonubes was isolated through the RT-PCR and RACE approach. The cDNA was 1,787-bp in length, including a 1,128-bp CDS, a 95-bp 5'UTR and a 564-bp 3'UTR. Genomic DNA containing the transcription region and 5'-flanking region was cloned based on the beta actin cDNA by Genome walker. A 3,000-bp beta actin gene promoter was then produced by PCR according to the sequences of the 5'-flanking region and the first intron. This promoter consisted of a 1,800-bp 5'-flanking region, and a 1,200-bp 5'-UTR. 3 transcription elements, CAAT box, CArG motif and TATA box were found in the 5'-flanking region. This promoter was inserted into the vector pDsRed2-1 and microinjected into fertilized eggs of Tanichthys albonubes to prove its transcription activity. The beta actin promoter and GH CDS of Tanichthys albonubes were then fused to construct an expression vector pTLA-GH. GH-transgenic Tanichthys albonubes was obtained by microinjection of the pTLA-GH into the fertilized eggs. Fast-growth individuals were observed in the transgenic group and the body weight of the largest individual was 2.1-fold that of the maximum in its non-transgenic siblings in 100 dph. In addition, a co-injection strategy was employed with pTLA-DsRed and pTLA-GH vector and proven to enhance the efficiency of GH-transgenic fish detection.