The Drosophila embargoed gene is required for larval progression and encodes the functional homolog of schizosaccharomyces Crm1.
The CRM1 (Exportin 1) protein is a receptor for leucine-rich nuclear export signal sequences. We have molecularly characterized the Drosophila melanogaster embargoed (emb) gene and find that it encodes a product with 49 and 71% sequence identity to the fission yeast Schizosaccharomyces pombe and human CRM1 proteins, respectively. We show that expression of the emb cDNA is sufficient to suppress the growth phenotype of both conditional-lethal and null S. pombe crm1(-) mutant strains, suggesting that emb encodes the functional homologue of the S. pombe Crm1 protein. Through mutagenesis screens we have recovered a series of recessive lethal emb mutations. There is a substantial maternal contribution of emb mRNA and animals hemizygous for our emb alleles can develop to second instar larvae but persist at this stage and consistently fail to undergo the molt to the third instar stage. We see a nuclear accumulation of endogenous actin in the intestinal epithelial cells of the emb mutant larvae, consistent with a role for the emb gene product in nuclear export of actin protein.
Collier
S
S
Department of Genetics, University of Cambridge, Cambridge CB2 3EJ, United Kingdom. simon.collier@man.ac.uk
Chan
H Y
HY
Toda
T
T
McKimmie
C
C
Johnson
G
G
Adler
P N
PN
O'Kane
C
C
Ashburner
M
M
D000199:Actins / Q000378:metabolism; D000483:Alleles; D000595:Amino Acid Sequence; D000818:Animals; D002352:Carrier Proteins / Q000235:genetics*; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism; D004330:Drosophila / Q000196:embryology / Q000235:genetics*; D004848:Epithelium / Q000378:metabolism; D005838:Genotype; D006579:Heterozygote; D006801:Humans; D017403:In Situ Hybridization; D028884:Karyopherins; D007814:Larva / Q000235:genetics / Q000502:physiology*; D008957:Models, Genetic; D008969:Molecular Sequence Data; D016296:Mutagenesis; D009154:Mutation; D010641:Phenotype; D018160:Receptors, Cytoplasmic and Nuclear; D012568:Schizosaccharomyces / Q000235:genetics*; D017386:Sequence Homology, Amino Acid; D013489:Suppression, Genetic; D014157:Transcription Factors / Q000235:genetics* / Q000502:physiology*; D000097606:Exportin 1 Protein
D000199:Actins; D002352:Carrier Proteins; D028884:Karyopherins; D018160:Receptors, Cytoplasmic and Nuclear; D014157:Transcription Factors; D000097606:Exportin 1 Protein