A DNA-binding protein apparently silences foreign DNA in Salmonella and perhaps other bacteria, helping regulate what they incorporate into their genomes, researchers reported in the June 8 online edition of Science.
This protein and other molecules could help protect against the potentially harmful effects of horizontal gene transfer while leaving open the door for beneficial genes to eventually get expressed, according to the paper. By helping bacteria distinguish between self- and foreign DNA, they "might be viewed as a primitive immune system," study author Ferric Fang at University of Washington in Seattle told The Scientist.
The researchers investigated H-NS (histone-like nucleoid structuring protein), which belongs to a family of small Gram-negative bacterial proteins that bind to DNA with relatively low sequence specificity -- important to any potential role in suppressing foreign DNA, which can be varied in sequence. Prior experiments showed H-NS can behave as a transcriptional repressor and affect ...
