Expression profiling by whole-genome interspecies microarray hybridization reveals differential gene expression in procyclic promastigotes, lesion-derived amastigotes, and axenic amastigotes in Leishmania mexicana

• Published in: Molecular and biochemical parasitology Vol. 146; no. 2; pp. 198 - 218
• Main Authors: Holzer, Timothy R., McMaster, W.R., Forney, James D.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.04.2006
• Subjects: Animals; Axenic amastigotes; Expression profiling; Gene Expression Profiling; Gene Expression Regulation; Genome, Protozoan; Interspecies; Leishmania; Leishmania major; Leishmania major - genetics; Leishmania mexicana; Leishmania mexicana - genetics; Leishmania mexicana - growth & development; mRNA; Oligonucleotide Array Sequence Analysis; Oligonucleotide microarray; Polymerase Chain Reaction; Protozoan Proteins - genetics; RNA, Messenger - analysis; RNA, Protozoan - analysis; Transcription, Genetic; Axenic amastigotes; mRNA; Expression profiling; Interspecies; Leishmania; Oligonucleotide microarray
• ISSN: 0166-6851; 1872-9428
• DOI: 10.1016/j.molbiopara.2005.12.009

We examined the Leishmania mexicana transcriptome to identify differentially regulated mRNAs using high-density whole-genome oligonucleotide microarrays designed from the genome data of a closely related species, Leishmania major. Statistical analysis on array hybridization data representing 8156 predicted coding regions revealed 288 genes (3.5% of all genes) whose steady-state mRNA levels meet criteria for differential regulation between promastigotes and lesion-derived amastigotes. Interestingly, sample comparison of promastigotes to axenic amastigotes resulted in only 17 genes (0.2%) that meet the same statistical criteria for differential regulation. The reduced number of regulated genes is a consequence of an increase in the magnitude of the transcript levels in cells under axenic conditions. The expression data for a subset of genes was validated by quantitative PCR. Our studies show that interspecies hybridization on microarrays can be used to analyze closely related protozoan parasites, that axenic culture conditions may alter amastigote transcript abundance, and that there is only a relatively modest change in abundance of a few mRNAs between morphologically distinct promastigote and amastigote cultured cells. Leishmania may represent an alternative paradigm for eukaryotic differentiation with minimal contributions from changes in mRNA abundance.