Skip to main content

Evidence for bacteriophage T7 tail extension during DNA injection

12Citations
Citations of this article
50Readers
Mendeley users who have this article in their library.

This artice is free to access.

Abstract

Background. Electron micrographs of bacteriophage T7 reveal a tail shorter than needed to reach host cytoplasm during infection-initiating injection of a T7 DNA molecule through the tail and cell envelope. However, recent data indicate that internal T7 proteins are injected before the DNA molecule is injected. Thus, bacteriophage/host adsorption potentially causes internal proteins to become external and lengthen the tail for DNA injection. But, the proposed adsorption-induced tail lengthening has never been visualized. Findings. In the present study, electron microscopy of particles in T7 lysates reveals a needle-like capsid extension that attaches partially emptied bacteriophage T7 capsids to non-capsid vesicles and sometimes enters an attached vesicle. This extension is 40-55 nm long, 1.7-2.4× longer than the T7 tail and likely to be the proposed lengthened tail. The extension is 8-11 nm in diameter, thinner than most of the tail, with an axial hole 3-4 nm in diameter. Though the bound vesicles are not identified by microscopy, these vesicles resemble the major vesicles in T7 lysates, found to be E. coli outer membrane vesicles by non-denaturing agarose gel electrophoresis, followed by mass spectrometry. Conclusion. The observed lengthened tail is long enough to reach host cytoplasm during DNA injection. Its channel is wide enough to be a conduit for DNA injection and narrow enough to clamp DNA during a previously observed stalling/re-starting of injection. However, its outer diameter is too large to explain formation by passing of an intact assembly through any known capsid hole unless the hole is widened. © 2008 Serwer et al; licensee BioMed Central Ltd.

Cite

CITATION STYLE

APA

Serwer, P., Wright, E. T., Hakala, K. W., & Weintraub, S. T. (2008). Evidence for bacteriophage T7 tail extension during DNA injection. BMC Research Notes, 1. https://doi.org/10.1186/1756-0500-1-36

Register to see more suggestions

Mendeley helps you to discover research relevant for your work.

Already have an account?

Save time finding and organizing research with Mendeley

Sign up for free