Murti K G, Prescott D M
Laboratory of Virology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA.
Proc Natl Acad Sci U S A. 1999 Dec 7;96(25):14436-9. doi: 10.1073/pnas.96.25.14436.
The end of a telomeric DNA sequence isolated from a polytene chromosome of a hypotrichous ciliate folds back and hybridizes with downstream telomeric sequence to form a t loop that is stable in the absence of protein and DNA cross-linking. The single-stranded, telomeric DNA sequence at the end of a macronuclear molecule does not form a t loop but, instead, is complexed with a heterodimeric, telomere-binding protein. Thus, two mechanisms for capping the ends of DNA molecules are used in the same cell.
从一种纤毛虫的多线染色体中分离出的端粒DNA序列的末端会折回并与下游的端粒序列杂交,形成一个t环,该t环在没有蛋白质和DNA交联的情况下是稳定的。大核分子末端的单链端粒DNA序列不会形成t环,而是与一种异二聚体端粒结合蛋白复合。因此,在同一细胞中使用了两种封闭DNA分子末端的机制。