Premium
Dictyostelium discoideum : a useful model system to evaluate the function of queuine and of the Q‐family of tRNAs
Author(s) -
Ott G.,
Kersten H.,
Nishimura S.
Publication year - 1982
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(82)80941-1
Subject(s) - function (biology) , dictyostelium discoideum , library science , combinatorics , biology , computer science , mathematics , genetics , gene
The nucleoside queuosine (Q) is found in the first position of the anticodon of tRNATy r, tRNA His, tRNAAsp and tRNA Asn of eubacteria and eukaryotes except yeast [1]. In eukaryotes queuine is inserted into the tRNAs in exchange for guanine by the enzyme queuine: guanine tRNAtransglycosylase [2,3]. Experiments with germ-free mice, fed on queuine-free diet, showed that mice do not synthesize queuine de novo [4,5]. The modification queuine in the Q-family of tRNA was found to be incomplete in tumours from various sources and to change in cells and tissues undergoing differentiation or ageing [6-10]. The role of queuine in these processes is unknown. Here, we show that Dictyostelium discoideum can be applied as a model system to evaluate the biological significance of queuine. When myxamoebae of the axenic strain AX-2 are grown in a well-defined synthetic medium supplemented with yeast extract but without peptone their tRNAs comprise guanine in place of queuine. The addition of queuine to the medium, at 10 -7 M, causes an almost complete modification of the corresponding tRNAs. Analysis of tRNA from the wildtype strain, NC-4, that needs E. coli B/r for growth indicates that bacteria supply D. discoideum with queuine.