Genetic basis of the difference in alcohol dehydrogenase expression between Drosophila melanogaster and Drosophila simulans.

Abstract

Drosophila melanogaster and its sibling species, Drosophila simulans, differ in expression of the enzyme alcohol dehydrogenase (ADH). Adult melanogaster flies that are homozygous for the Slow allozyme have approximately twice the level of ADH activity and crossreacting material as simulans adults. There is no corresponding difference in ADH mRNA, however, so this difference in ADH protein level is evidently due to a difference in the rate of translation of the two RNAs and/or to a difference in protein stability. Here we report an interspecific gene-transfer experiment, using P-element transformation, to determine whether this expression difference is due to genetic background differences between the species (trans-acting modifiers) or to cis-acting factors within the Adh gene. When the Adh genes from D. melanogaster and D. simulans are put into the same genetic background, there is no detectable difference in their level of expression. The level is relatively high in the melanogaster background and relatively low in the simulans background. Therefore, the interspecific difference in Adh expression is due entirely to trans-acting modifiers, in spite of the many sequence differences between the Adh genes of the two species, which include two amino acid substitutions.Drosophila melanogaster and its sibling species, Drosophila simulans, are essentially cosmopolitan in distribution and live in close association with man (1). Both species utilize fermenting fruits in which ethanol concentrations range up to several percent by volume (2, 3), but D. melanogaster appears to be more adapted to high alcohol environments than D. simulans. In laboratory toxicity tests, melanogaster adults consistently show a higher level of tolerance to ethanol and other alcohols than simulans adults (4)(5)(6)(7)(8). This difference in tolerance may be due to a difference in alcohol dehydrogenase (ADH; alcohol:NAD' oxidoreductase, EC 1.1.1.1) expression between the species.The ADH enzyme of D. melanogaster clearly plays an important role in alcohol detoxification and metabolism. Flies homozygous for a null allele of Adh are extremely sensitive to the toxic effects of environmental alcohols (9). More than 90% of the ethanol that is metabolized to lipid in larvae goes through a pathway that is dependent on ADH activity (10). Furthermore, genetic variation in ADH activity levels in melanogaster, particularly the difference between allozymes, is frequently associated with variation in tolerance to ethanol and other alcohols (for review, see refs. 11 and 12).The D. melanogaster Adh gene produces two different transcripts, which are differentially expressed during development but produce identical proteins (13, 14) (see Fig. 1). We have shown that the timing of usage of the two promoters during development is very similar in melanogaster and simulans (15). We have also compared the pattern of Adh expression throughout development in the two species by measuring ADH activity, ADH-crossreacting material (CRM), and ADH mRNA for several st...

Compensatory cis-trans Evolution and the Dysregulation of Gene Expression in Interspecific Hybrids of Drosophila

“…The key variables of the model, such as binding affinity and number of binding sites in the promoter, can be assayed (e.g., Oda et al 1998;Stormo and Fields 1998;Shaw et al 2002). Furthermore, the requisite technology exists to transfer individual Drosophila genes and their promoters between species (e.g., Laurie et al 1990;Wittkopp et al 2002). Tissue specificity of expression of these genes in the parental species and in their F 1 hybrids should also be examined.…”

Further Study on the Esterase Patterns of Sibling Species in the Drosophila saltans Subgroup (saltans Group): Intraspecific and Interspecific Variations in the Development

“…One of the systems that has contributed more significantly to the study of gene variation in expression and regulatory mechanisms in tissues and developmental stages is that of the alcohol dehydrogenase genes (Adh). In Drosophila, these genes have been extensively used in studies of species in the melanogaster subgroup (Cohn & Moore, 1988;Laurie et al, 1990;Wu, Mote & Brennan, 1990), in the mulleri complex of the repleta group (Fischer & Maniatis, 1988) and also in the Hawaiian picturewinged species (Brennan, Wu & Berry, 1988;Wu, Mote & Brennan, 1990;Fang & Brennan, 1992). In addition to information on the tissue-and stagespecific variation of expression and on the control mechanisms at the molecular level, ontogenetic studies on enzyme systems of close species may also be valuable for understanding basic changes which occurred during evolution within a species group (Prakash & Reddy, 1978;Oakeshott et al, 1993).…”

Membrane lipid physiology and toxin catabolism underlie ethanol and acetic acid tolerance inDrosophila melanogaster

“…The molecular, biochemical and thermostability differences between Adh variants have been well characterized (Anderson and McDonald, 1983;Chambers et al, 1984;Geer et al, 1993;Laurie et al, 1990;Milkman, 1976). The Adh-F allele confers greater ADH activity, but the Adh-S allele can maintain activity at higher temperatures (Anderson and McDonald, 1983;Milkman, 1976).…”