YMDD motif in hepatitis B virus DNA polymerase influences on replication and lamivudine resistance: A study by in vitro full-length viral DNA transfection.

Important note: Information in this article was accurate in 1999. The state of the art may have changed since the publication date.

YMDD motif in hepatitis B virus DNA polymerase influences on replication and lamivudine resistance: A study by in vitro full-length viral DNA transfection.

Hepatology. 1999 Mar;29(3):939-45. Unique Identifier : AIDSLINE MED/99162390
Ono-Nita SK; Kato N; Shiratori Y; Masaki T; Lan KH; Carrilho FJ; Omata M; Second Department of Internal Medicine, Faculty of Medicine,; University of Tokyo, Tokyo, Japan.

Abstract: Recently, lamivudine used to treat patients with hepatitis B virus (HBV) infection was revealed to have potent antiviral activity. However, HBV resistance to lamivudine has been reported and shown to have amino acid substitutions in the methionine residue of the conserved tyrosine (Y), methionine (M), aspartate (D), aspartate (D) motif of RNA-dependent DNA polymerase. To explore the consequences of substitutions in this motif (YMDD), we made 7 variants by substituting the methionine of the YMDD motif with isoleucine (I), valine (V), alanine (A), leucine (L), lysine (K), arginine (R), and threonine (T). Replication ability of these variants was evaluated by transfection into human hepatoma cells. Sensitivity to lamivudine was tested for replication-competent variants. Four variants with hydrophobic substitutions (I, V, A, and L) remained replication-competent, whereas 3 others with hydrophilic substitutions (K, R, and T) exhibited impaired replication. Of the 4 replication-competent variants, 2 (I and V) were resistant, and 2 (A and L) were sensitive to lamivudine. Because the polymerase and the surface gene overlap, the introduction of these mutations affected the secretion of hepatitis B surface antigen (HBsAg), namely 4 variants (I, V, L, and R) secreted HBsAg, whereas 3 variants (A, K, and T) did not. Our study elucidated that only one amino acid substitution in the YMDD motif was sufficient to cause lamivudine resistance in vitro. As a result of replication competence and lamivudine sensitivity, only viruses having YIDD or YVDD sequences may appear during treatment with lamivudine. This in vitro system could be used to study HBV mutations, replication competence, and their susceptibility to antivirals.

Keywords: JOURNAL ARTICLE Amino Acid Sequence/GENETICS Aspartic Acid/GENETICS Base Sequence/GENETICS Cell Line/IMMUNOLOGY Drug Resistance/GENETICS DNA-Directed DNA Polymerase/*GENETICS/*PHYSIOLOGY DNA, Viral/GENETICS Hepatitis B Surface Antigens/ANALYSIS Hepatitis B Virus/*GENETICS/IMMUNOLOGY Human Immunohistochemistry Lamivudine/*THERAPEUTIC USE Male Methionine/GENETICS Middle Age Molecular Sequence Data Reverse Transcriptase Inhibitors/*THERAPEUTIC USE Support, Non-U.S. Gov't Transfection Tyrosine/GENETICS Variation (Genetics)/PHYSIOLOGY
990630
A9960929

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