Gene amplification as a developmental strategy: isolation of two developmental amplicons in Drosophila.
Gene amplification is known to be critical for upregulating gene expression in a few cases, but the extent to which amplification is utilized in the development of diverse organisms remains unknown. By quantifying genomic DNA hybridization to microarrays to assay gene copy number, we identified two additional developmental amplicons in the follicle cells of the Drosophila ovary. Both amplicons contain genes which, following their amplification, are expressed in the follicle cells, and the expression of three of these genes becomes restricted to specialized follicle cells late in differentiation. Genetic analysis establishes that at least one of these genes, yellow-g, is critical for follicle cell function, because mutations in yellow-g disrupt eggshell integrity. Thus, during follicle cell differentiation the entire genome is overreplicated as the cells become polyploid, and subsequently specific genomic intervals are overreplicated to facilitate gene expression.
Claycomb
Julie M
JM
Whitehead Institute and Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA.
Benasutti
Matt
M
Bosco
Giovanni
G
Fenger
Douglas D
DD
Orr-Weaver
Terry L
TL
D000818:Animals; D002454:Cell Differentiation / Q000235:genetics*; D019070:Cell Lineage / Q000235:genetics; D004261:DNA Replication / Q000235:genetics; D042522:DNA Replication Timing / Q000235:genetics; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism; D004331:Drosophila melanogaster / Q000166:cytology / Q000196:embryology* / Q000235:genetics*; D005260:Female; D005784:Gene Amplification / Q000235:genetics*; D018507:Gene Expression Regulation, Developmental / Q000235:genetics*; D009154:Mutation / Q000235:genetics; D009865:Oocytes / Q000166:cytology / Q000378:metabolism; D009866:Oogenesis / Q000235:genetics*; D006080:Ovarian Follicle / Q000166:cytology / Q000196:embryology / Q000378:metabolism; D011123:Polyploidy
D029721:Drosophila Proteins; C050680:y protein, Drosophila