Arch Virol (2004) 149: 2013–2024
Two self-splicing group I introns interrupt two late
transcribed genes of prolate-headed Lactobacillus
delbrueckii phage JCL1032
and T. Alatossava
Department of Biology, University of Oulu, Oulu, Finland
Department of Food Technology, University of Helsinki, Helsinki, Finland
Received November 3, 2003; accepted March 1, 2004
Published online June 9, 2004
Summary. Two group I introns were detected from the late gene region of the
prolate-headed phage JCL1032 of Lactobacillus delbrueckii. Introns JCL-I1 and
JCL-I2 interrupt orf602 and orf1868 encoding a phage terminase large subunit
(TerL, 69.7 kDa) and a putative tape measure protein (TMP, 202 kDa), respectively.
The introns JCL-I1 (226 bp) and JCL-I2 (322 bp) were efﬁciently self-spliced
in vivo. Both introns were classiﬁed to the subgroup IA1 having all the conserved
structures necessary for splicing, but lacking the ability to encode endonucleases
or other gene products. The introns JCL-I1 and JCL-I2 shared restricted nucleotide
sequence similarity with each other and with the group I terL intron of Lb.
delbrueckii phage LL-H. No match was found for JCL-I1 in the homology searches.
Instead, the primary sequence from the joining region of P8 and P7 to P9 of the
intron JCL-I2 was homologous to the group I intron of Bacillus mojavensis; the
orf142 introns I1, I2 and I3 of Staphylococcus aureus phage Twort; the group I
intron of phage Bastille (Bacillus thuringiensis); and to the group IA3 intron of
Group I introns are small intervening sequences (IVS), which are transcribed
and excised from the primary transcript by RNA splicing to generate the ma-
ture RNA . The distribution of group I introns is broad: they are found in
plants, fungi, ﬂagellates, cyanobacteria, proteobacteria, Gram-positive bacteria
Nucleotide sequence data reported are deposited in the GenBank under accession
numbers AY392558 and AY392559.