276
Anthology of Human Repetitive DNA
5
AAAA-3
R
U5
PBS
PPT
U3
R
tRNA
5
AAAA-3
R
U5
PBS
PPT
U3
R
DNA synthesis
AAAA-3
PBS
PPT
U3
R
RH
AAAA-3
PBS
PPT
U3
R
First strand transfer
Second strand
transfer
R
U5
PBS
PPT
DNA synthesis
+
RH
PPT
U3
R
U5
U3
R
U5
PBS
U3
R
U5 PBS
PPT
U3
R
U5
DNA synthesis
+
RH
DNA synthesis
PBS
PPT
U3
R
U5
U3
R
U
5
P
B
S
U3
R
U
5
P
B
S
U3
R U5 PBS
PPT
U3
R
U5
LTR
LTR
Fig. 9
Reverse transcription of the retroviral RNA. Dotted lines
mark newly synthesized DNAs; green, plus-strand DNA; red,
minus-strand DNA; RH, RNaseH digestion of RNAs. (See color
plate p. xxiv).
accompanied by digestion of the RNA
template, except for a short RNaseH-
resistant polypurine tract (PPT).
5. The 3
0
end of the PPT primes plus-
strand DNA synthesis, which continues
until the PBS-like portion of the tRNA
molecule is reverse transcribed. As a
result, the so-called
plus-strand strong-
stop DNA
is generated.
6. RNaseH
digests
the
PBS-annealed
tRNA molecule.
7. The second strand transfer is per-
formed by annealing the complemen-
tary PBS segments present at the
termini of the plus-strand and minus-
strand DNAs.
8. The plus and minus DNA strands
serve as templates for each other.
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