p53 BINDS TO A SPECIFIC DNA SEQUENCEResearchers have shown that normal p53 tumor suppressorprotein binds to a specific DNA sequence.

The scientists, from Johns Hopkins University, AppliedbioTechnology Inc. and Columbia University, reported last weekin Science that p53 recognizes a sequence as short as 33 basepairs in length. The sequence appears to be associated withsites on the DNA where replication begins.

Mutations in p53 that inactivate the protein's tumorsuppressor activity occur in a large variety of cancers,including lung, colon, breast, ovary, bladder and brain cancer.

The researchers also show that two of the most commoncancer-associated mutant p53 proteins cannot bind to the DNAsequence. Understanding how p53 interacts with this and otherDNA sequences may help explain how normal p53 controls cellgrowth and why mutated forms of the gene lead to cancer. --Carol Talkington Verser, Ph.D

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