Drosophila males double transcription of their single X chromosome to equalize X-linked gene expression with females, which carry two X chromosomes. Increased transcription requires the Male-Specific Lethal (MSL) complex. The MSL2 protein is essential component of the MSL complex. MSL2 is the only protein that is strictly limited to males. MSL2 together with MSL1 forms the core of the MSL complex. The global effect of msl2 mutation on gene expression was measured by microarray analysis. We found that expression of the X chromosome was decreased in msl21 male larvae, supporting the involvement of MSL2 in the up-regulation of X-linked genes. However, there was no change in expression of 4th chromosomal and heterochromatic genes. This finding is broadly comparable to reports of reduced X chromosome expression following msl2 RNAi knockdown in S2 cells. Hence MSL2 is required for up-regulation of male X chromosome where as it is not necessary for normal expression of 4th chromosomal genes and heterochromatic genes in Drosophila melanogaster males. Experiment Overall Design: Total RNA was prepared from groups of 50 (or more in case of smaller larvae) third instar larvae by TRIzol (Invitrogen) extraction and purified using the RNeasy kit (Qiagen). Three independent RNA preparations for each genotype served as templates for probe synthesis. Affymetrix Drosophila Genome 2.0 chips were hybridized to these probes (Santa Clara, CA). Affymetrix Gene expression data was background corrected, normalized and summarized into a one expression value per sample and probeset using the RMA (robust multi-array average) algorithm. Changes in gene expression (log2 fold changes) were determined by comparing the mean RMA expression values in the msl21 sample to the mean RMA expression values in the msl21/+ samples.
Cyp6a17 DOWN in 'msl2 mutant' vs 'wild type genotype'
ImpE1 UP in 'msl2 mutant' vs 'wild type genotype'
Cht4 UP in 'msl2 mutant' vs 'wild type genotype'
to DOWN in 'msl2 mutant' vs 'wild type genotype'
CG8420 UP in 'msl2 mutant' vs 'wild type genotype'
CG8736 DOWN in 'msl2 mutant' vs 'wild type genotype'
Cht9 UP in 'msl2 mutant' vs 'wild type genotype'
tobi UP in 'msl2 mutant' vs 'wild type genotype'
Mal-A6 UP in 'msl2 mutant' vs 'wild type genotype'
Rac2 DOWN in 'msl2 mutant' vs 'wild type genotype'
Mal-A1 UP in 'msl2 mutant' vs 'wild type genotype'
Mal-A4 UP in 'msl2 mutant' vs 'wild type genotype'
CG40486 DOWN in 'msl2 mutant' vs 'wild type genotype'
l(2)efl DOWN in 'msl2 mutant' vs 'wild type genotype'
CG13461 UP in 'msl2 mutant' vs 'wild type genotype'
CG11893 DOWN in 'msl2 mutant' vs 'wild type genotype'
CG14205 UP in 'msl2 mutant' vs 'wild type genotype'
CG42640 DOWN in 'msl2 mutant' vs 'wild type genotype'
CG17672 UP in 'msl2 mutant' vs 'wild type genotype'
neo UP in 'msl2 mutant' vs 'wild type genotype'
Zip3 UP in 'msl2 mutant' vs 'wild type genotype'
TepI DOWN in 'msl2 mutant' vs 'wild type genotype'
mey UP in 'msl2 mutant' vs 'wild type genotype'
CG3588 UP in 'msl2 mutant' vs 'wild type genotype'
Mur89F UP in 'msl2 mutant' vs 'wild type genotype'
TwdlF UP in 'msl2 mutant' vs 'wild type genotype'
CG10799 DOWN in 'msl2 mutant' vs 'wild type genotype'
CR33318 DOWN in 'msl2 mutant' vs 'wild type genotype'
Cyp6d5 UP in 'msl2 mutant' vs 'wild type genotype'
CG31089 UP in 'msl2 mutant' vs 'wild type genotype'
lectin-24A DOWN in 'msl2 mutant' vs 'wild type genotype'
CG10140 DOWN in 'msl2 mutant' vs 'wild type genotype'
CG4363 UP in 'msl2 mutant' vs 'wild type genotype'
ninaD DOWN in 'msl2 mutant' vs 'wild type genotype'
CG14621 DOWN in 'msl2 mutant' vs 'wild type genotype'
CG14777 DOWN in 'msl2 mutant' vs 'wild type genotype'
Analysis of 'msl2 mutant' vs 'wild type genotype'
Mal-A8 UP in 'msl2 mutant' vs 'wild type genotype'
CG31148 UP in 'msl2 mutant' vs 'wild type genotype'
CG3191 DOWN in 'msl2 mutant' vs 'wild type genotype'
CG42822 UP in 'msl2 mutant' vs 'wild type genotype'
LysP UP in 'msl2 mutant' vs 'wild type genotype'
(Sample) organism/Drosophila melanogaster
Amyrel UP in 'msl2 mutant' vs 'wild type genotype'
lcs UP in 'msl2 mutant' vs 'wild type genotype'
CG10154 DOWN in 'msl2 mutant' vs 'wild type genotype'
(Sample) developmental stage/3rd instar larva
CG15553 DOWN in 'msl2 mutant' vs 'wild type genotype'
Cyp4p2 UP in 'msl2 mutant' vs 'wild type genotype'
alphaPS4 DOWN in 'msl2 mutant' vs 'wild type genotype'
CG31676 DOWN in 'msl2 mutant' vs 'wild type genotype'
(Factor value) GENOTYPE/wild type genotype