In search of vertebrate telomeric proteins

Indirect evidence suggests that vertebrate chromosome ends carry a protective nucleoprotein cap containing specific telomeric proteins. Telomeric proteins could explain the stringent sequence requirements for de novo telomere formation, aspects of telomere length regulation, the unusual chromatin structure detectable in some vertebrate telomeres, and the attachment of telomeric DNA to the nuclear matrix. Although telomeric proteins have been identified in unicellular organisms, vertebrate telomeric proteins are not well characterized. The search for these factors is discussed in this review.