Genetic analyses suggest that alterations in gene expression at the molecular and tissue levels can have profound effects on aging for multi-cellular organisms. However, much remains unknown about the normal pattern of genetic changes in different tissues and how these tissues interact during aging. To investigate tissue-specific aging systematically, we measured expression profiles of aging in Drosophila melanogaster in seven tissues representing nervous, muscular, digestive, renal, reproductive, and storage systems. In each tissue, we identified hundreds of age-related genes mostly showing gradual changes of transcript levels with age. Age-relatedgenes showed clear tissue-specific transcriptional patterns; less than 10% of age-related genes in each tissue shared expression patterns with any other tissue; less than 20% of age-related biological processes were shared between tissues. A significant portion of tissue-specific age-related genes are those involved in physiological functions regulated by the corresponding tissue. However, limited overlaps of age-related function groups among tissues particularly those involved in proteasome function suggest some common mechanisms of transcription regulation in aging across tissues. This study defined global, temporal and spatial changes associated withaging at the molecular and tissue levels. Analyses indicated that different tissues might age in different patterns or at different rates. This study addressed comprehensively the relationship of age-related changes among different tissues in one organism, providing a foundation to address tissue-specific regulation in aging. RNA was then amplified by a one-step linear amplification protocol to generate amplified RNA (aRNA). Experiment aRNA refers to amplified RNA from flies of 15, 20, 30, 45 and 60 days old, and reference aRNA refers to amplified RNA from flies of 3 days old, and experiment and reference aRNAs were labeled with fluorescent dye Cy3 and Cy5, respectively. For each tissue, RNA from the corresponding tissue of 3-day old flies was used as the reference RNA and expression profiles at each of the five age-points was measured twice by using independently prepared duplicated samples. Keywords: Drosophila melanogaster; Tissue-specific; Brain; Muscle; Gut; Malpighian tubule; Accessory gland; Testis; Adipose tissue; Genome-wide, aging
Overall design
Seven types of tissues or organs of the male fly strain w1118 , accessory gland, testis, brain, gut, malpighian tubule, dorsal thoracic muscle and abdominal fat body were hand dissected out of flies at age of 3, 15, 20, 30, 45 and 60 days old. Tissues or organs from four males of the same age were pooled together and used for each RNA sample preparation.
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