JOURNAL OF BACTERIOLOGY, JUlY 1992, p. 4525-4529
Vol. 174, No.
0021-9193/92/144525-05$02.00/0
14
Copyright C 1992, American Society for Microbiology
MINIREVIEW Short, Interspersed Repetitive DNA Sequences in Prokaryotic Genomes JAMES R. LUPSKI1,2 AND GEORGE M. WEINSTOCK3* Institute for Molecular Genetics' and Department of Pediatrics,2 Baylor College of Medicine, Houston, Texas 77030, and Department of Biochemistry and Molecular Biology, The University of Texas Health Science Center, P.O. Box 20708, 6431 Fannin Street, Houston, Texas 772253
Repeated sequences are present in the genomes of all organisms. The DNA sequence organization of eukaryotic genomes consists of numerous repeats interspersed with single-copy sequences. This organization has been elucidated through renaturation rate studies of denatured DNA (2). The best-characterized eukaryotic interspersed repetitive DNA sequences are the repeats in the Alu family that have been characterized in mammalian genomes (29, 55). In the human genome of 3 x 109 bp, the 300-bp Alu sequence represents approximately 3 to 6% of the mass, indicating that there are approximately 300,000 copies per haploid genome (55). Interspersed repetitive sequences in numerous prokaryotic and eukaryotic microorganisms have recently been described (Table 1). The ubiquitous nature and seemingly random chromosomal distribution of these repeats in prokaryotic genomes suggests that like more-complex eukaryotes, the DNA sequence arrangement in the genomes of eubacteria may consist of short repeats interspersed with longer single-copy sequences. Although the precise functions of repetitive sequences in prokaryotic genomes are obscure, their presence can be exploited for several applications and molecular genetic manipulations. Prokaryotic genomes contain a variety of low-copy-number repeated sequences, such as insertion elements, rRNA operons, tRNA genes, and other genes such as those belonging to the rhs gene family (32, 51, 52). These sequences may contribute to the evolution of chromosome structure through DNA rearrangements such as chromosomal deletions, duplications, and inversions (44). Repeated genes also provide mechanisms to enhance bacterial virulence, such as antigenic variation in Neissena gonorrhoeae (21) and other pathogens. The subject of this minireview is an additional group of repeated sequences, the interspersed repetitive sequence elements which are characterized as being short (usually
Vol. 174, No.
0021-9193/92/144525-05$02.00/0
14
Copyright C 1992, American Society for Microbiology
MINIREVIEW Short, Interspersed Repetitive DNA Sequences in Prokaryotic Genomes JAMES R. LUPSKI1,2 AND GEORGE M. WEINSTOCK3* Institute for Molecular Genetics' and Department of Pediatrics,2 Baylor College of Medicine, Houston, Texas 77030, and Department of Biochemistry and Molecular Biology, The University of Texas Health Science Center, P.O. Box 20708, 6431 Fannin Street, Houston, Texas 772253
Repeated sequences are present in the genomes of all organisms. The DNA sequence organization of eukaryotic genomes consists of numerous repeats interspersed with single-copy sequences. This organization has been elucidated through renaturation rate studies of denatured DNA (2). The best-characterized eukaryotic interspersed repetitive DNA sequences are the repeats in the Alu family that have been characterized in mammalian genomes (29, 55). In the human genome of 3 x 109 bp, the 300-bp Alu sequence represents approximately 3 to 6% of the mass, indicating that there are approximately 300,000 copies per haploid genome (55). Interspersed repetitive sequences in numerous prokaryotic and eukaryotic microorganisms have recently been described (Table 1). The ubiquitous nature and seemingly random chromosomal distribution of these repeats in prokaryotic genomes suggests that like more-complex eukaryotes, the DNA sequence arrangement in the genomes of eubacteria may consist of short repeats interspersed with longer single-copy sequences. Although the precise functions of repetitive sequences in prokaryotic genomes are obscure, their presence can be exploited for several applications and molecular genetic manipulations. Prokaryotic genomes contain a variety of low-copy-number repeated sequences, such as insertion elements, rRNA operons, tRNA genes, and other genes such as those belonging to the rhs gene family (32, 51, 52). These sequences may contribute to the evolution of chromosome structure through DNA rearrangements such as chromosomal deletions, duplications, and inversions (44). Repeated genes also provide mechanisms to enhance bacterial virulence, such as antigenic variation in Neissena gonorrhoeae (21) and other pathogens. The subject of this minireview is an additional group of repeated sequences, the interspersed repetitive sequence elements which are characterized as being short (usually
