The length of a tetranucleotide repeat tract in <i>Haemophilus influenzae</i> determines the phase variation rate of a gene with homology to type III DNA methyltransferases

Abstract

The authors of the article by De Bolle et al. published in Molecular Microbiology volume 35, number 1 on pp. 211–222, wish to note that the mutation rates reported in their paper as being derived according to Drake (1991) (Proc Natl Acad Sci USA88: 7160–7164) were calculated using an incorrect version of the equation The correct form of the equation is, as reported in the text, Actual phase variation rates (column 4 of Table 1 in the original article), can be calculated by multiplying reported values by 2.12. A corrected version of Fig. 4 is printed below and the linear regression lines are now off-to-on y=8 × 10−6x− 5 × 10−5 and on-to-off y=2 × 10−5x− 2 × 10−4. We also note that the phase varation rates reported in Fig. 5 are equivalent to (A) 6, (B) 10 and (C) 22 5′-AGTC repeats respectively. The relative values and significance of results reported are unaltered. The authors apologize for any misunderstanding arising from this error. Influence of tetranucleotide repeat tract length on mutation rates in H. influenzae . Mutation rates were derived from the frequencies of variants using the method described by Drake (1991) (see Table 1). These rates were plotted against the total number of repeats within the repeat tract. The on-to-off and off-to-on directions of switching are represented by filled diamonds and filled squares respectively. Linear regression lines were fitted to the data using Microsoft Excel.