Lodestar subfamily

This subfamily is the only one within the Rad5/16 grouping which does not contain RING fingers in the major insertion site. The archetype of this subfamily is the D melanogaster Lodestar protein, first identified as an essential cell-cycle regulated protein localising to chromosomes during mitosis 1.

Subsequently it was recognised that the human homologue TTF2 acts to terminate elongating RNA pol I and pol II complexes independently of transcript length, possibly by directing clearing Pol II from the template 2.

TTF2 may also have a role in interphase termination, and in repair 2. This latter repair implication is interesting because no clear higher eukaryote homologue of S cerevisiae Rad5p has been identified and Lodestar subfamily members are present in higher eukaryotes but not fungi. TTF2 has been observed to rescue RNA polymerases stalled at lesions 3.

subfamily members
names associated with subfamily members
LDS, TTF2, hLodestar, HuF2, factor 2
references
1: Girdham, C. H. and D. M. Glover (1991). Chromosome tangling and breakage at anaphase result from mutations in lodestar, a Drosophila gene encoding a putative nucleoside triphosphate-binding protein. Genes Dev 5(10): 1786-99. PubMed
2: Jiang, Y., M. Liu, et al. (2004). Involvement of transcription termination factor 2 in mitotic repression of transcription elongation. Mol Cell 14(3): 375-85. PubMed
3: Hara, R., C. P. Selby, et al. (1999). Human transcription release factor 2 dissociates RNA polymerases I and II stalled at a cyclobutane thymine dimer. J Biol Chem 274(35): 24779-86. PubMed