| Autor: |
Purdy JE; Department of Medicine, University of Virginia, Charlottesville 22908, USA., Pho LT, Mann BJ, Petri WA Jr |
| Jazyk: |
angličtina |
| Zdroj: |
Molecular and biochemical parasitology [Mol Biochem Parasitol] 1996 Jun; Vol. 78 (1-2), pp. 91-103. |
| DOI: |
10.1016/s0166-6851(96)02614-x |
| Abstrakt: |
Entamoeba histolytica genomic organization and putative promoter elements appear to be distinct from both metazoan and better characterized protozoan organisms. The recent development of DNA-mediated transfection for E. histolytica enabled characterization of cis-acting promoter elements required for gene expression. A deletion and replacement analysis was conducted on the promoter of an E. histolytica gene encoding the heavy subunit of the N-acetyl-beta-D-galactosamine-specific adhesin (hgl5). Deletion of the DNA from -1000 bases to -272 bases upstream from the start of transcription of hgl5 did not decrease reporter gene expression. Subsequent nested deletions and 10-bp replacement mutagenesis identified four positive upstream regulatory elements between bases -219 to -200, -189 to -160, -69 to -60, and -49 to -40. A negative upstream regulatory element between bases -89 to -80 was conserved upstream of three other E. histolytica genes. Mutation of the previously unidentified 'GAAC' element conserved within the putative core promoter decreased reporter gene expression by 75%. Site directed mutagenesis of the putative TATA element decreased reporter gene expression by greater than 50%, while mutation of the putative initiator element resulted in a more modest decrease. This analysis suggests that E. histolytica promoters are unlike other protozoan promoters, with AT-rich upstream regulatory elements, a non-consensus TATA element, the "GAAC' element, and an unusual initiator element. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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