Mutation of the zebrafish nucleoporin elys sensitizes tissue progenitors to replication stress.
The recessive lethal mutation flotte lotte (flo) disrupts development of the zebrafish digestive system and other tissues. We show that flo encodes the ortholog of Mel-28/Elys, a highly conserved gene that has been shown to be required for nuclear integrity in worms and nuclear pore complex (NPC) assembly in amphibian and mammalian cells. Maternal elys expression sustains zebrafish flo mutants to larval stages when cells in proliferative tissues that lack nuclear pores undergo cell cycle arrest and apoptosis. p53 mutation rescues apoptosis in the flo retina and optic tectum, but not in the intestine, where the checkpoint kinase Chk2 is activated. Chk2 inhibition and replication stress induced by DNA synthesis inhibitors were lethal to flo larvae. By contrast, flo mutants were not sensitized to agents that cause DNA double strand breaks, thus showing that loss of Elys disrupts responses to selected replication inhibitors. Elys binds Mcm2-7 complexes derived from Xenopus egg extracts. Mutation of elys reduced chromatin binding of Mcm2, but not binding of Mcm3 or Mcm4 in the flo intestine. These in vivo data indicate a role for Elys in Mcm2-chromatin interactions. Furthermore, they support a recently proposed model in which replication origins licensed by excess Mcm2-7 are required for the survival of human cells exposed to replication stress.
Davuluri
Gangarao
G
Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA, USA.
Gong
Weilong
W
Yusuff
Shamila
S
Lorent
Kristin
K
Muthumani
Manimegalai
M
Dolan
Amy C
AC
Pack
Michael
M
D000595:Amino Acid Sequence; D000818:Animals; D017209:Apoptosis; D002453:Cell Cycle; D064447:Checkpoint Kinase 2; D004249:DNA Damage; D004261:DNA Replication; D016158:Genes, p53; D007413:Intestinal Mucosa / Q000378:metabolism; D007422:Intestines / Q000166:cytology / Q000196:embryology; D008969:Molecular Sequence Data; D009154:Mutation; D028861:Nuclear Pore Complex Proteins / Q000737:chemistry / Q000235:genetics* / Q000502:physiology*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012160:Retina / Q000166:cytology / Q000196:embryology / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism; D015027:Zebrafish / Q000235:genetics* / Q000254:growth & development / Q000502:physiology; D029961:Zebrafish Proteins / Q000737:chemistry / Q000235:genetics* / Q000502:physiology*
C533929:AHCTF1 protein, zebrafish; D028861:Nuclear Pore Complex Proteins; D012333:RNA, Messenger; D014157:Transcription Factors; D029961:Zebrafish Proteins; D064447:Checkpoint Kinase 2; C578634:CHEK2 protein, human; D017346:Protein Serine-Threonine Kinases