A novel putative transcription factor protein MYT2 that preferentially binds supercoiled DNA and induces DNA synthesis in quiescent cells

Myelin transcription factor 2 (MYT2), a putative transcription factor found in the human central nervous system, was cloned from an expression cDNA li brary from human T-cells, MYT2 shares weak similarity to bacterial type I t opoisomerases and shares 63% sequence identity to a replicase from Leuconos toc mesenteroides. MYT2 preferentially binds supercoiled DNA (scDNA), Incub ation of MYT2 and scDNA at or above equal molar ratios generated topoisomer -like patterns that were abolished by deproteination. Thus, MYT2 appears to relax scDNA via a non-enzymatic mechanism. The banding pattern of MYT2-scD NA complexes was shown to be quantisized, saturable and sequence-independen t. Microinjection of MYT2 mRNA induced G(0) growth-arrested NIH 3T3 cells t o enter the S phase of the cell cycle, (C) 2000 Federation of European Bioc hemical Societies.