DNA sequences of the tail fiber genes of bacteriophage P2: evidence for horizontal transfer of tail fiber genes among unrelated bacteriophages

Abstract

We have determined the DNA sequence of the bacteriophage P2 tail genes G and H, which code for polypeptides of 175 and 669 residues, respectively. Gene H probably codes for the distal part of the P2 tail fiber, since the deduced sequence of its product contains regions similar to tail fiber proteins from phages Mu, P1, lambda, K3, and T2. The similarities of the carboxy-terminal portions of the P2, Mu, ann P1 tail fiber proteins may explain the observation that these phages in general have the same host range. The P2 H gene product is similar to the products of both lambda open reading frame (ORF) 401 (stf, side tail fiber) and its downstream ORF, ORF 314. If 1 bp is inserted near the end of ORF 401, this reading frame becomes fused with ORF 314, creating an ORF that may represent the complete stf gene that encodes a 774-amino-acid-long side tail fiber protein. Thus, a frameshift mutation seems to be present in the common laboratory strain of lambda. Gene G of P2 probably codes for a protein required for assembly of the tail fibers of the virion. The entire G gene product is very similar to the products of genes U and U' of phage Mu; a region of these proteins is also found in the tail fiber assembly proteins of phages TuIa, TuIb, T4, and lambda. The similarities in the tail fiber genes of phages of different families provide evidence that illegitimate recombination occurs at previously unappreciated levels and that phages are taking advantage of the gene pool available to them to alter their host ranges under selective pressures.

Two recombination-dependent DNA replication pathways of bacteriophage T4, and their roles in mutagenesis and horizontal gene transfer

“…The example of the dCTPase genes shows that in this situation, horizontal gene transfer can generate mosaic sequence divergence within essential genes, in turn, establishing species barriers. Similar mosaic arrangements in other genes of the T-even (69,71) and other phages (67) are also most readily explained by the mechanism illustrated in Fig. 3.…”

“…Illegitimate site-specific recombination or transposition have been proposed to exchange entire gene modules of related functions (66). However, gene segments can also be exchanged or added (67)(68)(69)(70)(71). We have suggested that a combination of join-copy and join-cut-copy pathways, together with heteroduplex repair (Fig.…”

Ecogenomics and genome landscapes of marine Pseudoalteromonas phage H105/1

“…In the 'tail fibre, host recognition' module, ORF 45 contains a domain of the Phage tail fibre adhesin Gp38 Pfam family (Table 1). In T2-like phages, gp38 is responsible for recognition of host cell receptors (Haggard-Ljungquist et al, 1992); it is thus considered to be a critical factor for change and is one of the most rapidly evolving components of a phage-host system.…”

Bacteriophage P2

“…58 Gene H encodes the tail fiber protein, and gene G is required for tail fiber assembly. 59 The tail genes F I , F II , E, T, U and D comprise a single transcription unit. 50,52 Gene F I encodes the tail sheath, and F II encodes the tail tube.…”