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ANNETTE DEICHMANN AND KLAUS DEICHMANN
• EMBL 3 and 4
These are so-called lambda replacement vectors, in which a part ofthat
does not contain any genesessential for DNA replication and lytic development has been removed (Frischauf 1983). Thereby, the recombinant
phage lose the ability to form prophage. These vectors accomodate inserts of about 15-23 kb in length. Polylinker sequences flanking both sites
of the insert region simplify cloning and recovery. Inserts that areoutside
of the range of 15-23 kb in length will prohibit packaging of the recombinant phage. These vectors are suitable for genomic libraries, especially
those produced by partial digestion of genomic DNA using the restriction enzyme Mbo I. EMBL 3 and 4 contain restriction enzyme sites in
reverse order.
MB derivatives
M13 is a filamentous, male-specific coliphage, that is about 6.4 kb in length.
A so-called male E. coli strain is capable of forming F-pili (F'or p+) which are
encoded by an episome and are necessary for phage adherence (Messing
1977, Sambrook 1989, Wu 1983). M13 sharesextensive homology and similiar replication mechanisms with other filamentaus phage such as fd
and fl. During infection of E. coli host cells, single-stranded phage DNA
(+strand) is converted into double-stranded replicative forms and then amplified. These double-stranded DNA intermediates are used in cloning reactions. Normally they are used in the cell to produce progeny as singlestranded DNA. The DNA molecules are packaged into protein coats and
extruded without causing celllysis. However, infected cells tend to grow
slower producing cloudy plaques (in contrast to clear plaques following lytic infections). Due to the single-stranded state, M13 carriers exhibit greater
flexibility of insert as one major advantage. Furthermore, single-stranded
DNA can be used directly in sequencing reactions.
• M13mp18/M13mp19
These vectors are modern, M13-derived cloning vectors. The native vector has been supplemented by the insertion of the lac promotor/operator
region encoding the first 145 amino acids of the ß-galactosidase gene of
E. coli (lacZ a-peptide gene). Using suitable, defective E. coli celllines
(JM103, XLlblue) the gene product of lacZ will restore ß-galactosidase
activity (Langley 1975). Induction ofprotein synthesis bythe use ofiPTG
(isopropyl-ß-D-thiogalactopyranoside) in the growth medium will cause
X-gal (5-bromo-4-chloro-3-indolyl-ß-D-galactoside), a colorless dye in
the medium, tobe metabolized into a blue pigment. The multiple cloning
region (MCR) ofM13mp18/19 has been inserted into the coding region of
the ß-galactosidase gene without disrupting its function. However, in-
ANNETTE DEICHMANN AND KLAUS DEICHMANN
• EMBL 3 and 4
These are so-called lambda replacement vectors, in which a part ofthat
does not contain any genesessential for DNA replication and lytic development has been removed (Frischauf 1983). Thereby, the recombinant
phage lose the ability to form prophage. These vectors accomodate inserts of about 15-23 kb in length. Polylinker sequences flanking both sites
of the insert region simplify cloning and recovery. Inserts that areoutside
of the range of 15-23 kb in length will prohibit packaging of the recombinant phage. These vectors are suitable for genomic libraries, especially
those produced by partial digestion of genomic DNA using the restriction enzyme Mbo I. EMBL 3 and 4 contain restriction enzyme sites in
reverse order.
MB derivatives
M13 is a filamentous, male-specific coliphage, that is about 6.4 kb in length.
A so-called male E. coli strain is capable of forming F-pili (F'or p+) which are
encoded by an episome and are necessary for phage adherence (Messing
1977, Sambrook 1989, Wu 1983). M13 sharesextensive homology and similiar replication mechanisms with other filamentaus phage such as fd
and fl. During infection of E. coli host cells, single-stranded phage DNA
(+strand) is converted into double-stranded replicative forms and then amplified. These double-stranded DNA intermediates are used in cloning reactions. Normally they are used in the cell to produce progeny as singlestranded DNA. The DNA molecules are packaged into protein coats and
extruded without causing celllysis. However, infected cells tend to grow
slower producing cloudy plaques (in contrast to clear plaques following lytic infections). Due to the single-stranded state, M13 carriers exhibit greater
flexibility of insert as one major advantage. Furthermore, single-stranded
DNA can be used directly in sequencing reactions.
• M13mp18/M13mp19
These vectors are modern, M13-derived cloning vectors. The native vector has been supplemented by the insertion of the lac promotor/operator
region encoding the first 145 amino acids of the ß-galactosidase gene of
E. coli (lacZ a-peptide gene). Using suitable, defective E. coli celllines
(JM103, XLlblue) the gene product of lacZ will restore ß-galactosidase
activity (Langley 1975). Induction ofprotein synthesis bythe use ofiPTG
(isopropyl-ß-D-thiogalactopyranoside) in the growth medium will cause
X-gal (5-bromo-4-chloro-3-indolyl-ß-D-galactoside), a colorless dye in
the medium, tobe metabolized into a blue pigment. The multiple cloning
region (MCR) ofM13mp18/19 has been inserted into the coding region of
the ß-galactosidase gene without disrupting its function. However, in-