Figure 19-4: Diagrammatic representation of a 15 kbp region covering the junction between early (D genes) and late genes (assembled from three sequences, accession numbers M64047, M24354 and AJ001191). The position of a strong terminator of transcription (ter) is indicated. The D9 DNA polymerase is preceded by a promoter (not shown). D10 is a putative helicase, D11 and 14 have no obvious functions or homologues of known function. Genes D12 and 13 are thought to be part of a repair nuclease. The D15 exonuclease gene overlaps with the deoxyuridine triphosphatase (dut) gene, both of which are served by a promoter just upstream. The long tail fibre gene (ltf) is transcribed in the opposite orientation to the early genes. In addition to the reading frames shown, the fragment contains numerous ORFs with little or no homology to any database deposits. An enlargement of a region defined by EcoRI and BglII restriction sites is shown. Tandem promoters P31A and P31B are separated by 100 bases (39). Their -10 sequences are both overlapped by a 20 bp direct repeats (triangles). P31B possesses an 18 bp imperfect palindrome (diamond) that overlaps with the P31B -35 element. A cryptic 94 amino acid ORF is situated downstream and must be present in order to clone fragments carrying P31B (39). (for better image quality, click here for tif image, which may be quite large; may also require screen refreshing plus special software to view; or view larger tif in separate window)

Figure 19-1, Figure 19-2, Figure 19-3, Figure 19-4

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