The C-terminal region of Rad2p is important for cell cycle regulation and lifespan in the presence of DNA damage.

초록

Yeast RAD2 is a homolog of the human xeroderma pigmentosum group G gene (XPG). Rad2 and XPG proteins, endonucleases that function in nucleotide excision repair, are highly conserved in their structure and functions. The C-teminal truncation of XPG is known to cause a human hereditary disorder, Cockayne syndrome (CS) that is characterized by growth retardation, impaired neurological development, mental retardation and premature aging.In addition to its endonuclease function, Rad2p was shown to have a function in transcription. However, defects in endonuclease activity and transcription are not sufficient to explaib the symptoms of CS. Recently, RAD2-over-expression was shown to evoke mitotic catastrophe implying its involvement in cell cycle regulation.In this study, we show that the C-terminal region of Rad2p is important for maintaining cell growth after UV damage. We also show that the Rad2p C-teminal region is pivotal for replicative lifespan in the presence of DNA damage. These results indicate that the Rad2p C-terminal region may have an unidentified function or mechanism, beside its well known endonuclease activity, in its growth regulatory role upon UV irradiation that might be the underlying cause of CS.