NELF complex is a ~ 300 kDa multiprotein complex composed of 5 peptides (A - E): ~66,61,59,58 and 46 kDa. All these peptides are required for NELF-mediated inhibition of Pol II elongation. NELF complex has been reported to bind to the pre-formed DSIF:RNA Pol II complex that may act as a scaffold for its binding. NELF-A is suspected to be involved in Wolf-Hirschhorn syndrome.
Binding of DSIF:NELF to RNA Pol II CTD results in abortive termination of early elongation steps by the growing transcripts.