Targeted entry via somatostatin receptors using a novel modified retrovirus glycoprotein that delivers genes at levels comparable to those of wild-type viral glycoproteins.
Here we report a novel viral glycoprotein created by replacing a natural receptor-binding sequence of the ecotropic Moloney murine leukemia virus envelope glycoprotein with the peptide ligand somatostatin. This new chimeric glycoprotein, which has been named the Sst receptor binding site (Sst-RBS), gives targeted transduction based on three criteria: (i) a gain of the use of a new entry receptor not used by any known virus; (ii) targeted entry at levels comparable to gene delivery by wild-type ecotropic Moloney murine leukemia virus and vesicular stomatitis virus (VSV) G glycoproteins; and (iii) a loss of the use of the natural ecotropic virus receptor. Retroviral vectors coated with Sst-RBS gained the ability to bind and transduce human 293 cells expressing somatostatin receptors. Their infection was specific to target somatostatin receptors, since a synthetic somatostatin peptide inhibited infection in a dose-dependent manner and the ability to transduce mouse cells bearing the natural ecotropic receptor was effectively lost. Importantly, vectors coated with the Sst-RBS glycoprotein gave targeted entry of up to 1 × 10(6) transducing U/ml, a level comparable to that seen with infection of vectors coated with the parental wild-type ecotropic Moloney murine leukemia virus glycoprotein through the ecotropic receptor and approaching that of infection of VSV G-coated vectors through the VSV receptor. To our knowledge, this is the first example of a glycoprotein that gives targeted entry of retroviral vectors at levels comparable to the natural capacity of viral envelope glycoproteins.
Department of Microbiology, Immunology & Biochemistry, University of Tennessee Health Science Center, Memphis, Tennessee 38163, USA.
Fang
F
Li
Byoung Y
BY
Ryu
Robin L
RL
Krueger
Scott A
SA
Heldt
Lorraine M
LM
Albritton
D000818:Animals; D001665:Binding Sites; D002460:Cell Line; D018390:Gene Targeting / Q000295:instrumentation; D018014:Gene Transfer Techniques / Q000295:instrumentation*; D005822:Genetic Vectors / Q000737:chemistry / Q000235:genetics / Q000502:physiology; D006801:Humans; D051379:Mice; D008958:Models, Molecular; D008969:Molecular Sequence Data; D008979:Moloney murine leukemia virus / Q000737:chemistry / Q000235:genetics* / Q000502:physiology; D011485:Protein Binding; D015202:Protein Engineering; D017481:Receptors, Somatostatin / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011991:Receptors, Virus / Q000235:genetics / Q000378:metabolism; D013004:Somatostatin / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D014759:Viral Envelope Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D053586:Virus Internalization
D017481:Receptors, Somatostatin; D011991:Receptors, Virus; D014759:Viral Envelope Proteins; D013004:Somatostatin