Biology Reference
In-Depth Information
KR-rich region
DNA binding
B
1
473
A
C
A
B
C
HPV16 13-ASATQLYKTCKQAGTCPPD-31 24-QAGTCPPDIIPKVEGKTIADQI
-
45 108-
LVEETSFIDAGAP
-
120
HPV6 12-*******Q***LT******-30 23-LT******V*****HN******
-
44 107-*I**SAI*N****
-
119
HPV11 11-*******Q***AT******-29 22-AT******V*****HT******-43 106-*I**SAI*N****-118
HPV18 12-**V*D*******S******-30 23-QS******VV*****T*L**K*-44 106-*I*DS*VVTS***-118
HPV31 12-*******Q***A*****S*-30 24-A*****S*V***I*HT******-45 108-****SGIV*V***-120
HPV33 12-*******Q***AT******-30 23-AT******V******S******-44 107-*I******E****-119
HPV45 12-****D**R****S******-30 23-QS******V*N****T*L**K*-44 106-***DS*VVAS***-118
HPV52 12-*******Q***AS******-30 23-AS******V******T*****L-44 107-MI***T**ES***-119
HPV58 12-*******Q***AS******-30 23-AS******V******T******-44 107-*I**S********-119
Fig. 3.
L2 regions binding to the cell surface. Region A: aa13 to 31.
34
Region B: aa24 to 45.
31
Region C: aa108 to 120.
33
Amino acid sequences of
selected mucosal HPV L2s homologous to regions A, B, and C are aligned.
(aa1-128)/GFP is co-precipitated with b-actin in a lysate of radio-
labeled SiHa cells, a human cell line derived from cervical cancer, with
anti-GFP antibody. The co-precipitation is mediated by a complex
formation between the HPV16 L2 region of aa25-45 with b-actin
(Fig. 3, Region B). HPV16 pseudovirions containing L2 with a dele-
tion of aa25-45 dramatically reduce infectivity, suggesting that the
binding of L2 with b-actin is critical for infection.
We indicated that the HPV16 L2 region of aa108-126 plays an
important role in the initial steps of infection.
32
The L2 peptide
(aa108-126) tagged with GFP (L2/108-126/GFP) attaches to the
HeLa cell surface at a low temperature and enters the cytoplasm when
the temperature is raised to 37
(Fig. 3, Region C). L2/108-120/
GFP does not bind to the cells pretreated with trypsin, suggesting
that the cellular binding partner is a protein. Synthetic L2 peptide of
aa108-120 interferes with the infectivity of the pseudovirions in
COS-1 cells, suggesting the presence of a cell surface receptor for
the aa108-120 region of L2, to which L2/108-126/GFP can bind.
The aa substitutions that prevent L2/108-126/GFP from binding
lower the infectivity of the pseudovirion having the same mutations.
The data suggest that the N-terminal segment of L2 aa108-126,
°
