QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

Vol. 18, Issue 6, 2179-2191, June 2007

This Article Full Text Full Text (PDF) All Versions of this Article: E07-01-0074v2 18/6/2179    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Cui, Z. Articles by DiMario, P. J. Search for Related Content PubMed PubMed Citation Articles by Cui, Z. Articles by DiMario, P. J.

RNAi Knockdown of Nopp140 Induces Minute-like Phenotypes in Drosophila

Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803

Submitted January 29, 2007; Revised March 13, 2007; Accepted March 20, 2007
Monitoring Editor: A. Gregory Matera

Nopp140 associates with small nucleolar RNPs to chaperone pre-rRNA processing and ribosome assembly. Alternative splicing yields two isoforms in Drosophila: Nopp140-True is homologous to vertebrate Nopp140 particularly in its carboxy terminus, whereas Nopp140-RGG contains a glycine and arginine-rich (RGG) carboxy terminus typically found in vertebrate nucleolin. Loss of ribosome function or production at critical points in development leads to Minute phenotypes in Drosophila or the Treacher Collins syndrome (TCS) in humans. To ascertain the functional significance of Nopp140 in Drosophila development, we expressed interfering RNA using the GAL4/UAS system. Reverse transcription-PCR showed variable losses of Nopp140 mRNA in larvae from separate RNAi-expressing transgenic lines, whereas immunofluorescence microscopy with isoform-specific antibodies showed losses of Nopp140 in imaginal and polyploid tissues. Phenotypic expression correlated with the percent loss of Nopp140 transcripts: a 50% loss correlated with larval and pupal lethality, disrupted nuclear structures, and in some cases melanotic tumors, whereas a 30% loss correlated with adult wing, leg, and tergite deformities. We consider these adult phenotypes to be Minute-like and reminiscent of human craniofacial malformations associated with TCS. Similarly, overexpression of either isoform caused embryonic and larval lethality, thus indicating proper expression of Nopp140 is critical for normal development.

Address correspondence to: Patrick DiMario (pdimari{at}lsu.edu).

Abbreviations used: Nopp140, nucleolar phosphoprotein of 140 kilodaltons; RNAi, RNA interference; RGG, glycine and arginine–rich domain; snoRNPs, small nucleolar ribonucleoprotein particles; UASs, upstream activating sequences; GFP, green fluorescent protein; TCS, Treacher Collins syndrome.