Targeted localized degradation of Paired protein in Drosophila development.
BACKGROUND
Selective spatial regulation of gene expression lies at the core of pattern formation in the embryo. In the fruit fly Drosophila, localized transcriptional regulation accounts for much of the embryonic pattern.


RESULTS
We identified a gene, partner of paired (ppa), whose properties suggest that localized receptors for protein degradation are integrated into regulatory networks of transcription factors to ensure robust spatial regulation of gene expression. We found that the Ppa protein interacts with the Pax transcription factor Paired (Prd) and contains an F-box, a motif found in receptors for ubiquitin-mediated protein degradation. In normal development, Prd functions only in cells in which ppa mRNA expression has been repressed by another segmentation protein, Even-skipped (Eve). When ppa was expressed ectopically in these cells, Prd protein, but not mRNA, levels diminished. When ppa function was removed from cells that express prd mRNA, Prd protein levels increased.


CONCLUSIONS
Ppa co-ordinates Prd degradation and is important for expression of Prd to be correctly localized. In the presence of Ppa, Prd protein is targeted for degradation at sites where its mis-expression would disrupt development. In the absence of Ppa, Prd is longer-lived and regulates downstream target genes.
Raj
L
L
Department of Biology, Wesleyan University, Middletown, Connecticut 06459, USA.
Vivekanand
P
P
Das
T K
TK
Badam
E
E
Fernandes
M
M
Finley
R L
RL
Brent
R
R
Appel
L F
LF
Hanes
S D
SD
Weir
M
M
D000595:Amino Acid Sequence; D000818:Animals; D002352:Carrier Proteins / Q000235:genetics*; D004330:Drosophila / Q000196:embryology* / Q000235:genetics*; D029721:Drosophila Proteins; D004625:Embryo, Nonmammalian / Q000502:physiology; D005775:Gastrula / Q000502:physiology; D018507:Gene Expression Regulation, Developmental; D018398:Homeodomain Proteins / Q000378:metabolism*; D019476:Insect Proteins / Q000235:genetics; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000235:genetics; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014158:Transcription, Genetic
D002352:Carrier Proteins; D029721:Drosophila Proteins; D018398:Homeodomain Proteins; D019476:Insect Proteins; C419987:Ppa protein, Drosophila; D012333:RNA, Messenger; C489935:prd protein, Drosophila