REGULATION OF EXOENZYME GENES IN STREPTOCOCCUS MUTANS

The sacU operon of Bacillus subtilis has previously been shown to regulate
the expression of extracellular enzymes involved in the degradation of
complex polysaccharides and proteins. Southern blot analysis of
Streptococcus mutans chromosomal DNA using the sacU operon as a gene probe
indicates that this organism also contains similar genes. Given that
degradative genes similar to those mentioned above have been demonstrated
to be involved in cariogenesis, it is then likely that. these sacU-like
genes play a major role in determining the virulence of S. mutans. To
study this hypothesis, the sacU-like genes of S. mutans GS-5 will be cloned
and sequenced. The cloned DNA will then be utilized to construct a sacU
null mutation by insertional mutagenesis and those genes affected by this
mutation will be determined by assaying for the alteration of the synthesis
of various exoenzymes.