High impact information on CHL4

• Centromere DNA introduced into the cell is unable to promote kinetochore assembly in the absence of CHL4 [1].
• Mutations in chl4/mcm17/ctf17 segregate dicentric chromosomes through successive cell divisions without breakage, indicating that only one of the two centromeres is functional [1].
• In contrast, established centromeres retain their segregation capacity for greater than 25 generations after depletion of Chl4p [1].
• A genomic clone of CHL4 was isolated by complementation of the chl4-1 mutation and was physically mapped to the right arm of chromosome IV near the SUP2 gene [2].
• Nucleotide sequence analysis of CHL4 clone revealed a 1.4-kb open reading frame coding for a 53-kD predicted protein which does not have homology to published proteins [2].

Biological context of CHL4

• Identification and cloning of the CHL4 gene controlling chromosome segregation in yeast [2].
• A strain containing a null allele of CHL4 is viable under standard growth conditions but has a temperature-sensitive phenotype (conditional lethality at 36 degrees) [2].
• Moreover, nonessential dicentric plasmids were maintained stably without any rearrangements during many generations in the chl4 mutant [2].
• In one of the seven mutants analyzed, chl4, dicentric plasmids did not depress cell division [2].
• Analysis of the segregation of a marked chromosome indicated that sister chromatid nondisjunction and sister chromatid loss contributed equally to chromosome malsegregation in the chl4 mutant [2].

Other interactions of CHL4

• We have identified four new genetic loci: CHL2 (on chromosome XII), CHL3 (on chromosome XII); CHL4 (on chromosome IV), and CHL5 (on chromosome IX), controlling mitotic transmission of yeast chromosomes [3].
• This analysis revealed Sgo1, Chl4, and Iml3 to be important for retaining centromeric cohesin until the onset of anaphase II [4].

References