The molecular architecture of CenH3-deficient holocentromeres in Lepidoptera is dependent on transcriptional and chromatin dynamics

Aruni Senaratne (1, 1) , Héloïse Muller , Kelsey Fryer , Ines Drinnenberg (1, 1)

1 Dynamique du noyau [Institut Curie]

Despite their essentiality for chromosome segregation, centromeres are diverse among eukaryotes and embody two main configurations: mono- and holocentromeres, referring respectively to a localized or unrestricted distribution of centromeric activity. Previous studies revealed that holocentricity in many insects coincides with the loss of the otherwise essential centromere component CenH3 (CENP-A), suggesting a molecular link between the two events. In this study, we leveraged recently-identified centromere components to map and characterize the centromeres of Bombyx mori. This uncovered a robust correlation between centromere profiles and regions of low chromatin dynamics. Transcriptional perturbation experiments showed that low chromatin activity is crucial for centromere formation in B. mori . Our study points to a novel mechanism of centromere formation that occurs in a manner recessive to the chromosome-wide chromatin landscape. Based on similar profiles in additional Lepidoptera, we propose an evolutionarily conserved mechanism that underlies the establishment of holocentromeres through loss of centromere specificity.

Domaines: Sciences du Vivant [q-bio]; Génomique, Transcriptomique et Protéomique [q-bio.GN]

Aruni Senaratne, Héloïse Muller, Kelsey Fryer, Ines Drinnenberg. The molecular architecture of CenH3-deficient holocentromeres in Lepidoptera is dependent on transcriptional and chromatin dynamics. 2020. ⟨hal-03063828⟩