Structural And Functional Analysis Of Human HAS3 Promoter

Hyaluronan synthase 3 (HAS3) is a hyaluronan-synthesizing enzyme which plays a critical role in epidermis and tumor development. To further investigate its transcriptional regulation, HAS3 gene promoter has been cloned and identified in the present study. At first, the transcriptional start sites for HAS3 gene have been identified by 5' RACE (rapid amplification of cDNA ends) and bioinformatic analysis. 5' RACE assay also revealed two novel transcriptional variants of HAS3 gene with distinct transcriptional start sites. Furthermore ,Several overlapping genomic fragments from the 5'- flanking region of HAS3 gene have been then coloned into pGL3-basic vector to construct HAS3 promoter reporters. Luciferase reporter assay in-dicated that HAS3 promoter region is mainly located in a 450-bp region nearby the major transcriptional start site. Transcriptional factor binding analysis indicated that, HAS3 gene promoter lacks of classical TATA box, but contains classical GC box as well as other putative binding sites for tran-scriptional factors such as C/EBP. These results suggested that transcrip-tional factors such as Sp1 and C/EBP might be invovled in the transcriptional regualtion of HAS3 gene.