RT Journal Article
SR Electronic
T1 <em>Lhr</em> and <em>Hmr</em> are required for sister chromatid detachment during anaphase but not for centromere function
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 178046
DO 10.1101/178046
A1 Jacob A. Blum
A1 Silvia Bonaccorsi
A1 Marta Marzullo
A1 Valeria Palumbo
A1 Yukiko M. Yamashita
A1 Daniel A. Barbash
A1 Maurizio Gatti
YR 2017
UL http://biorxiv.org/content/early/2017/08/18/178046.abstract
AB Crosses between Drosophila melanogaster females and Drosophila simulans males produce hybrid sons that die at the larval stage. This hybrid lethality is suppressed by loss-of-function mutations in the D. melanogaster Hybrid male rescue (Hmr) or in the D. simulans Lethal hybrid rescue (Lhr) genes. Previous studies have shown that Hmr and Lhr interact with heterochromatin proteins and suppress expression of transposable elements within D. melanogaster. It also has been proposed that Hmr and Lhr function at the centromere. We examined mitotic divisions in larval brains from Hmr and Lhr single mutants and Hmr; Lhr double mutants in D. melanogaster. In none of the mutants did we observe defects in metaphase chromosome alignment or hyperploid cells, which are hallmarks of centromere or kinetochore dysfunction. In addition, we found that Hmr-HA and Lhr-HA do not localize to centromeres either during interphase or mitotic division. However, all mutants displayed anaphase bridges and chromosome aberrations resulting from the breakage of these bridges, predominantly at the euchromatin-heterochromatin junction. The few dividing cells present in hybrid males showed irregularly condensed chromosomes with fuzzy and often closely apposed sister chromatids. Despite this defect in condensation, chromosomes in hybrids managed to align on the metaphase plate and undergo anaphase. We conclude that there is no evidence for a centromeric function of Hmr and Lhr within D. melanogaster nor for a centromere defect causing hybrid lethality. Instead we find that Hmr and Lhr are required in D. melanogaster for detachment of sister chromatids during anaphase.