1022-7954/00/3612- $25.00 © 2000
Russian Journal of Genetics, Vol. 36, No. 12, 2000, pp. 1385–1394. Translated from Genetika, Vol. 36, No. 12, 2000, pp. 1645–1655.
Original Russian Text Copyright © 2000 by Bidnenko, Akhverdyan, Krylov.
(TP) D3112 and
TP Mu has similar
genetic organizations [1–5], although they are unre-
lated and do not display DNA–DNA homology. It was
found that repressor genes (
)p; regulatory genes
in D3112 and
in Mu; and genes
, which are
responsible for replication–transposition in both TPs,
[6–12], as well as the nonessential genome region, reg-
ulators of late gene transcription, and genes controlling
morphogenesis of the head and the tail [8, 13, 14] were
located similarly in the genomes of phages D3112 and
Mu. In addition, genes
, and, to a certain extent,
had similar functions in the two TPs.
Further studying functional homology between the
genes and gene groups of TPs D3112 and Mu required
a more detailed analysis of the roles of different genes
involved in the regulation of the phage expression.
When studying the transcription of TP D3112 (from
) genome in a homologous host, two tran-
scription waves were observed, which corresponded to
the early and late RNA syntheses . Early RNA syn-
thesis was independent of the D3112 replication–trans-
position, whereas late RNA synthesis required the
products of phage genes
and the locus containing the
mutation site  (hereinafter, locus
), as well
as effective replication of the phage [15, 16].
In this study, we carried out transcriptional mapping
of the D3112 genome. The data obtained allowed us to
determine the order in which different genomic regions
of the phage are transcribed and to estimate the tran-
scription rate during the lytic development. We suggest
a transcriptional map comprising six independent tran-
scriptional units corresponding to the main modules of
phage D3112. This map implies that the regulatory pat-
terns of the
TP D3112 and the
Mu are similar to each other. The roles of the regulatory
(repressors of early gene transcrip-
tion), as well as gene
tors of late gene transcription) are discussed.
MATERIALS AND METHODS
strain PAO1 was
obtained from B.W. Holloway (Australia).
We used phage D3112
mutants of this
phage for essential genes, including
phages with polar mutations, whose
as well as D3112
and B39s mutants  were
The methods used in experiments with bacterioph-
ages are described in .
Hottinger’s medium (meat digest) was used,
in the forms of liquid medium and agar medium, to
obtain and titrate the phage. The M9 basic medium 
was used in experiments where [
]RNA was obtained.
Transcriptional Mapping and Studying the Control
of Transcription of the
Transposable Phage D3112
E. M. Bidnenko, V. Z. Akhverdyan, and V. N. Krylov
State Research Institute of Genetics and Selection of Industrial Microorganisms, Moscow, 113545 Russia
Received December 19, 1997; in ﬁnal form, May 15, 2000
Regulation of transcription was studied in a wild-type transposable phage (TP) D3112 of
and its mutants for different genes. For this purpose, [
with denatured fragments from various regions of the D3112 genome bound to nitrocellulose ﬁlters was used.
A transcriptional map of TP D3112 was constructed based on the data obtained. The map comprised six inde-
pendent transcriptional units corresponding to the modular organization of the phage genome. Only the repres-
was transcribed in the lysogenic state. After repressor thermoinactivation, the
ceased, and transcription occurred in the same order as the genes (modules) were located on the D3112 phage
genetic map (from left to right):
(a negative regulator) and early genes
(controlling the replication–
transposition of the phage), nonessential genome region, genes
and the locus marked with the
(positive regulators of late gene transcription), the genes of the head morphogenesis, gene
(a positive reg-
ulator responsible for the lysogenic state), and the genes of the tail morphogenesis. Similarities between non-
homologous TPs D3112 of
and Mu of
with respect to genetic organization and
transcription regulation are discussed.