Biology Reference
In-Depth Information
Finally, how do the results above relate to the Ñmod/rescÒ model for CI? A number of
models have been put forward over the years, but all suffer from the same lack of detailed
information about the basic molecular mechanisms affected by Wolbachia . In this particular
case, the kinetic model proposed by Tram and Sullivan can be thought of as a speciÝc case
of mod/resc whereby ÑmodiÝcationÒ includes altering the ability of sperm to enter the Ýrst
mitosis and ÑrescueÒ is the ability of Wolbachia (in the egg) to synchronize the female
pronucleus to match the delay in sperm maturation. However, in many ways the mod/resc
model is akin to the original Ñlock-and-keyÒ model for enzyme action in that it is so general
and broad in scope as to include everything while at the same time excluding little or nothing.
As we now know, the lock-and-key model of enzyme action has been replaced by dynamic
models that include, for example, substrate-induced conformational change (induced Ýt),
binding of cofactors, and, most recently, enzyme action coupled to mechanochemical force
transduction in polymeric-protein systems (Dickinson and Purich, 2002). This last point is
relevant to the present discussion as the model was developed to explain bacterial motility
inside eukaryotic cells and underscores the extent to which prevailing models of enzyme action
(and, by analogy, Wolbachia action) must be modiÝed or altered to explain existing data. It
will be of great interest to follow the course of events as more cellular and molecular
mechanistic details of CI and Wolbachia action are discovered that will, it is hoped, provide
reÝned insights into the nature of Wolbachia -induced incompatibility.
ACKNOWLEDGMENTS
KB and HRB acknowledge funding by the European Commission (EUWOL, QLRT-2000-
01079). KB is supported by intramural funds of the University of Ioannina and by funding
from the Empirikion Foundation. HRB is supported by funding from the Biotechnology and
Biological Research Council (5/S11854) and the Natural Environment Research Council
(GR3/13199). TLK acknowledges support from the National Science Foundation (MCB-
0135166) and the Royal Society Wolfson Merit Award program. The authors thank Dr. Harriet
L. Harris and Dr. Stefan Oehler for reviewing the manuscript.
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