Arch Virol (1999) 144: 397–405
Analysis of the thymidine kinase genes of macropodid
herpesviruses 1 and 2
S. M. Lee
and G. A. Smith
Queensland Agricultural Biotechnology Centre, Queensland Department
of Primary Industries, Queensland, Australia
Department of Biochemistry, The University of Queensland, Queensland, Australia
Accepted August 27, 1998
Summary. The nucleotide sequences of the entire protein coding regions of the
thymidine kinase (TK) genes of macropodid herpesvirus type 1 (MaHV-1) and
type 2 (MaHV-2) were determined. The coding region of the MaHV-1 TK gene
was 984 bp long and was predicted to encode a polypeptide of 327 amino acids.
The coding region of the MaHV-2 TK gene was 1020 bp long and encoded
a polypeptide of 340 amino acids. Comparisons of their deduced amino acid
sequences with those of ﬁfteen other herpesviruses revealed close homology
to those of other alphaherpesviruses, particularly to human herpesvirus type 1
(HHV-1) and type 2 (HHV-2).
Macropodid herpesvirus 1 (MaHV-1) and macropodid herpesvirus 2 (MaHV-2)
have been a signiﬁcant cause of mortality and morbidity in macropods [2, 4, 20].
They cause fatal diseases characterised by pneumonia and hepatitis [2, 20] and
less severe clinical manifestation including the appearance of herpes-like vesicles
around the mouth, nose and ano-genital region . The presence of macropidid
herpesvirus-speciﬁc neutralising antibodies in many different kangaroo and
wallaby species in Australia suggests widespread infection by these viruses. A
23.1% prevalence of neutralising antibodies was detected among free-ranging
macropods and 41.4% in captive macropods .
Thymidine kinase (TK) is an enzyme that operates in the salvage pathway of
pyrimidine biosynthesis . It is one of the most extensively studied herpesvirus
genes . Although not essential for virus growth in vitro or in vivo it appears
to be an important determinant of herpesvirus pathogenicity . Herpesviruses
with defective TK genes (TK) have been used as attenuated and stable vaccine