Isolation and primary function detection of Nile tilapia (Oreochromis niloticus) β-actinpromoter

A 5′-flanking region and partial open reading frame (ORF) of the β-actingene (GenBank accession No. EF026001) of Nile tilapia (Oreochromis niloticus) was cloned by polymerase chain reaction (PCR) amplification. The segment included a 1643 bp regulatory sequence and a 90 bp partial ORF which encoded a 30-amino-acid peptide. The regulatory sequence comprised a 108 bp 5′ proximal promoter, the first untranslated exon and the first intron of the β-actingene. The proximal promoter region contained elements that were critical for transcription activity, including a CCAAT, TATA and CArG box located at –92, –29 and –62 bp upstream of the transcription initiation site, respectively. The regulatory sequence was inserted into the promoterless pDsRed2-1 vector to construct the expressing vector pNA-DsRed. The linearized pNA-DsRedwas microinjected into the fertilized eggs ofTanichthys albonubes. The expression of theDsRed2gene in transgenic fish could be observed under the microfluoroscope and anatomical lens. The results showed that the β-actingene promoter possessed effective transcription activity.