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Avian Adenovirus | 291

5’ 3’
3’ 5’

Stage I of DNA
replication

Displaced strands

Stage II of DNA
replication

Figure 10.3 Adenovirus DNA replication. One of the DNA strands serves as template for the synthesis of the daughter strand while the other
Figure 3. Adenovirus DNA replication. One of the DNA strands serves as template for the synthesis of the daughter strand while the other is
is displaced. The displaced DNA strand forms a ‘panhandle’ structure through annealing of the self-complementary termini. Synthesis of
displaced. The displaced DNA strand forms a “panhandle” structure through annealing of the self-complementary termini. Synthesis of the
daughter strand begins in one of the termini and disrupts the panhandle structure. Initiation of DNA synthesis from any of the parental strands is
the daughter strand begins in one of the termini and disrupts the panhandle structure. Initiation of DNA synthesis from any of the parental
mediated by the viral DNA polymerase and pTP. The priming reaction takes place by the formation of the pTP-deoxycytidine monophosphate
strands is mediated by the viral DNA polymerase and pTP. The priming reaction takes place by the formation of the pTP-deoxycytidine
(dCMP) complex that is catalyzed by the viral DNA polymerase. The pTP-dCMP serves to prime synthesis of the nascent DNA strand by the viral
monophosphate (dCMP) complex that is catalysed by the viral DNA polymerase. The pTP-dCMP serves to prime synthesis of the nascent
DNA polymerase. The elongation of the daughter strand involves separation of the viral DNA polymerase from pTP, which remains covalently
DNA strand by the viral DNA polymerase. The elongation of the daughter strand involves separation of the viral DNA polymerase from pTP,
attached to the 5’ end of both termini. The elongation of the daughter strand requires DBP to unwind the viral genome during synthesis. (From
which remains covalently attached to the 5′ end of both termini. The elongation of the daughter strand requires DBP to unwind the viral
Lechner, R.L., Kelly, Jr. T.J. Cell, 1977;12:1007–1020, with modifications.)
genome during synthesis.
Tripartite leader Penton 22 K 33K E3
52/
sequence 3 55 K III pVII V pVI Hexon (II) 100 K pVIII Fiber
23 K
1
(IV)
2
a)
(A) E3 Late L5
L4
L3
E1B L1 L2 L4 intermediate
E1A X VA I II E3
MLP
1 2 i 3
E2A
E2B
IVa2 E4
Bipartite leader
sequence
1 2 Fiber-1
Fiber-2 L6
pVIII
33K
100K-1 L5
100K-2
protease
Hexon (II) L4
ORF1 (dUTPase) pVI L3
ORF1C pX-1
ORF1B-1 pX-2 L2
ORF1B-2 pVII-1 ORF25
ORF2 pVII-2 L1 E5 ORF11
Penton (III)
b) pIIIa ORF8 (Gam-1)
(B) MLP 52K
TR-1 TR-1
pTP
pol E2 E6 ORF23-1
ORF13 ORF23-2
ORF22
ORF 33972-32989 E4
ORF19
Figure 4a. Transcriptional maps for human adenoviruses 2 and 5 (From Wold, W.S. and Gooding, L.R. Virology, 1991;184:1-8).
Figure 10.4 (A) Transcriptional maps for human adenoviruses 2 and 5 (reprinted from Virology, 184, Wold, W.S. and Gooding, L.R. Region
Figure 4b. Transcriptional map for fowl adenovirus 9 (From Ojkic, D., Krell, P. and Nagy, E. Virology, 2002;302;274–285, with
E3 of adenovirus: a cassette of genes involved in host immunosurveillance and virus–cell interactions,1–8, copyright 1991, with permission
modifications.) Mastadenovirus late transcripts contain a tripartite leader sequence whereas aviadenovirus late transcripts consist of
from Elsevier). (B) Transcriptional map for fowl adenovirus 9 (reprinted from Virology, 302, Ojkic, D., Krell, P. and Nagy, E. Unique features
a bipartite leader sequence. 274–285, copyright 2002, with permission from Elsevier). Mastadenovirus late transcripts contain a
of fowl adenovirus 9 gene transcription,
tripartite leader sequence whereas aviadenovirus late transcripts consist of a bipartite leader sequence.