Yun Y D, Davis R L
Department of Biochemistry, Michigan State University, East Lansing 48824.
Nucleic Acids Res. 1989 Oct 25;17(20):8313-26. doi: 10.1093/nar/17.20.8313.
Clones carrying sequences expressed at altered abundance levels in dunce mutants were isolated by differentially screening a genomic library with cDNA probes representing the RNA population from dunce+ flies and the RNA population from dunce mutant flies. These mutants have an elevated cAMP content, so some isolates potentially contain cAMP responsive genes. Two classes of clones were isolated. One class contains genes expressed at a higher steady state abundance level in dunce mutants compared to dunce+ flies and the other contains genes expressed at a lower steady state level in the mutants. The recovery of clones from the differential screen demonstrates that in addition to altering normal behavior, fertility, and cAMP metabolism, dunce mutation confers an alteration in the level of expression of certain genes. The class of clones carrying sequences which are overexpressed in the mutants have been characterized. These clones carry a common repetitive sequence which codes for a 5.5 kb poly(A)+ RNA - the RNA species found to be overexpressed in the mutants. Restriction analysis and hybridization experiments show these repetitive sequences to be members of the copia family of transposable elements. Administration of pharmacological agents to normal flies to increase cAMP levels leads to an increased steady state level of copia RNA. Thus, copia RNA metabolism appears to be influenced by cAMP levels.
通过用代表野生型果蝇RNA群体和dunce突变体果蝇RNA群体的cDNA探针差异筛选基因组文库，分离出了在dunce突变体中以改变的丰度水平表达序列的克隆。这些突变体的cAMP含量升高，因此一些分离物可能包含cAMP反应基因。分离出了两类克隆。一类包含与野生型果蝇相比在dunce突变体中以更高稳态丰度水平表达的基因，另一类包含在突变体中以较低稳态水平表达的基因。差异筛选中克隆的回收表明，除了改变正常行为、生育力和cAMP代谢外，dunce突变还导致某些基因表达水平的改变。已经对携带在突变体中过表达序列的克隆类别进行了表征。这些克隆携带一个共同的重复序列，该序列编码一种5.5 kb的聚腺苷酸化RNA——在突变体中发现过表达的RNA种类。限制性分析和杂交实验表明这些重复序列是转座因子copia家族的成员。给正常果蝇施用药物以提高cAMP水平会导致copia RNA的稳态水平升高。因此，copia RNA代谢似乎受cAMP水平影响。
