Source: Dissertation Abstracts International, Volume: 51-07, Section: B, page: 3357.

Adviser: David C. Ward.

Minute Virus of Mice is an autonomous parvovirus containing a single-stranded genome which is $\sp{\sim}$5 kilobases long. There are two overlapping transcription units with promoters at map unit 4 (P4 promoter) and 38 (P38 promoter). To define the functional elements responsible for the control of transcription from the P4 and P38 promoters, a series of 5$\sp\prime$ deletion and linker scanning mutants were constructed for both promoters. Transcriptional activity of the mutants for both promoters was assayed in both HeLa and A92L nuclear extracts by primer extension experiment. These analyses demonstrated that the essential DNA cis-elements of both promoters are a GC box and a TATA box.

To examine the DNA-protein interaction within the P4 promoter, DNase 1 footprinting and gel retardation competition assay were carried out. These experiments demonstrated that P4 GC box is interacting with a murine protein(s) which is similar but not identical to the human transcription factor, Sp1. To determine the transactivation of the P38 promoter by the viral non-structural protein(s), a series of in vivo reporter plasmids containing the wild-type P38 promoter as well as multiple linker scanning mutants were constructed and analyzed in A92L cells using a transient transfecton assay. The P38 promoter is an extremely weak promoter in vivo in the absence of the viral non-structural protein(s). When the viral non-structural protein(s) is introduced, the P38 promoter becomes a very strong promoter by transactivation. There is no cis-element(s) responsible for the transactivation within the P38 promoter suggesting that the transactivation is not mediated by the direct interaction between the viral non-structural protein(s) and the P38 promoter.