| The interaction between Rb and hsHec1p was reconstituted in a yeast strain in which human hsHEC 1 rescues the null mutation of scHEC 1 . ^^^ Expression of Rb reduced chromosome segregation errors fivefold in yeast cells sustained by a temperature sensitive ( ts ) hshec 1 113 allele and enhanced the ability of wild type hsHec1p to suppress lethality caused by a ts smc 1 mutation . ^^^ Expression of Rb restored part of the inactivated function of hshec 1 113p and thereby increased the DNA binding activity of Smc1p . ^^^ |