Cells grown statically in CDM (37°C) and harvested at OD600=0.2.
Extracted molecule
total RNA
Extraction protocol
RNA was isolated and purified using the High Pure RNA isolation kit (Roche diagnostics) as described (Hendriksen et al., 2007; Hendriksen et al., 2008a). Contaminating genomic DNA was removed by treatment with RNase-free DNase I (Roche diagnostics). RNA was isolated from three replicate cultures.
Label
Cy5
Label protocol
Total RNA was incubated for 16 h at 42°C in the presence of 400 U Superscript III RNase H reverse transcriptase (Invitrogen), 0.2 mM aminoallyl dUTP (Amersham), 0.5 mM dATP, 0.5 mM dCTP, 0.5 mM dGTP, 0.3 mM dTTP, and 3.2 g random nonamers. The synthesized cDNA was then labeled by coupling either Cy3 or Cy5 to the dUTP aminoallyl reactive group (CyScribe postlabeling kit; Amersham Biosciences) and was purified using a GFX PCR, DNA, and gel band purification kit (Amersham Biosciences).
Cells grown statically in CDM (37°C) and harvested at OD600=0.2.
Extracted molecule
total RNA
Extraction protocol
RNA was isolated and purified using the High Pure RNA isolation kit (Roche diagnostics) as described (Hendriksen et al., 2007; Hendriksen et al., 2008a). Contaminating genomic DNA was removed by treatment with RNase-free DNase I (Roche diagnostics). RNA was isolated from three replicate cultures.
Label
Cy3
Label protocol
Total RNA was incubated for 16 h at 42°C in the presence of 400 U Superscript III RNase H reverse transcriptase (Invitrogen), 0.2 mM aminoallyl dUTP (Amersham), 0.5 mM dATP, 0.5 mM dCTP, 0.5 mM dGTP, 0.3 mM dTTP, and 3.2 g random nonamers. The synthesized cDNA was then labeled by coupling either Cy3 or Cy5 to the dUTP aminoallyl reactive group (CyScribe postlabeling kit; Amersham Biosciences) and was purified using a GFX PCR, DNA, and gel band purification kit (Amersham Biosciences).
Hybridization protocol
The protocol was performed as described in Hendriksen et al., 2008 (PMID: 18024519)
Scan protocol
Images were acquired with GeneTac LS IV confocal laser scanner (Genomics Solutions).
Description
Microarray analysis was performed essentially as described (Hendriksen et al., 2007 [PMID: 17085554]; Hendriksen et al., 2008 [PMID: 18024519]). In short, 500 ml of CDM was inoculated with 10-20 colonies from agar plates, and these cultures were statically grown at 37°C. Samples for RNA isolation were taken when the cultures reached an optical density (OD600) of 0.2 (mid-log growth). RNA was isolated and purified using the High Pure RNA isolation kit (Roche diagnostics) as described (Hendriksen et al., 2007; Hendriksen et al., 2008a). Contaminating genomic DNA was removed by treatment with RNase-free DNase I (Roche diagnostics). RNA was isolated from three replicate cultures. Synthesis, subsequent labeling of cDNA, and microarray hybridization was performed as described (Hendriksen et al., 2007; Kloosterman et al., 2006 [16787930]).
Data processing
Dual-channel array images were analyzed with ArrayPro 4.5 software (Media Cybernetics Inc.). Spots were screened visually to identify those of low quality. Slide data were processed with MicroPreP as previously described (15, 18, 49). Prior to analysis, automatically and manually flagged spots and spots with very low background subtracted signal intensity (5% of the weakest spots [sum of Cy3 and Cy5 net signals]) were filtered out of all data sets.Net signal intensities were calculated by grid-based background subtraction. A grid-based Lowess transformation was performed for slide normalization, negative and empty values were removed, and outliers were removed by the deviation test. Expression ratios of mutant strain over the wild-type strain were calculated. Further analysis was performed with a Cyber-T Student t test for paired data.
