Subject: esterase queries Dear Dr Ashburner John Oakeshott passed your esterase queries on to me. We note that FlyBase lists the cytological site of alphaE7 as 84D3 - we would like to change that to 84D3-10 (see Russell et al. 1996, Insect Biochem. Molec. Biol. 26: 235). >FlyBase is curating your paper on the a-esterase cluster. Can any of these >be tied to Ali, Est9, Mce yet? If not, we will have to create new genes >for the sequenced ones. The work of Campbell et al. (Biochemical genetics, 35:17-40 , 1997, and Insect Biochemistry and Molecular Biology, in press) have shown that ALI and MCE in Lucilia cuprina are encoded by alleles of the LcaE7 gene (ie esterase E3 = ALI = MCE), the orthologue of DmaE7. Robin et al. (in prep) have confirmed by in vitro expression that DmaE7 encodes EST23 in D. melanogaster, which was shown by Spackman et al. (Biochemical Genetics 32:39 , 1994) to be the likely homologue of esterase E3 in Lucilia. The expressed product of DmaE7 also had ali-esterase and MCE activities. As yet we have not identified the gene encoding EST9. Comments on the status of the following genes: Est20 (Campbell et al., 1992, Insect Biochem Molec. Biol. 22:665 ) Est20 in D. melanogaster is most probably the orthologue of the p-esterase in D. virilis. The latter may be a minor component of JHE activity (Klebodarova et al.,1996, Insect Biochem. Molec. Biol. 26:829 ) but EST20 is not JHE. Est9 of Loukas (1981, DIS 66:85 ) This gene maps to chromosome 2R and is the orthologue of Est9 in D. subobscura. The esterase is localised to the adult head and is detected only when 1-leucyl-b-naphthylamide is used as a substrate together with a-naphthyl acetate. As far as we know the gene has not been cloned, nor was it identified by Healy et al. (1991, Biochemical Genetics 29:365 ). The nomenclature is unfortunate but we refer to it as 'Est9 of Loukas'. EstA (Mizianty and Case, 1971, J. Hered, 62: 345) This gene is most probably Est18 of Healy et al. (1991, Biochemical Genetics 29: 365). As far we know Est18 has been neither mapped nor cloned. EstF (Chang and Lin, 1990, Bull. Inst. Zool. Acad. Sinica, Taiwan 29: 81 and 1995, Zool. Studies 34: 47) This gene encodes an esterase dimer in D. albomicans that is polymorphic in natural populations. We have no idea where it maps or which of the D. melanogaster esterases it might be orthologous to. Regards, Robyn Russell Subject: Re: esterase queries Dear Robyn Russell Thank you very much for your detailed reply. Some questions: 1. You say that alphaE7 is 84D3-10; fine, but the others in this cluster are at 84D3, is that OK ? 2. I have merged the following three FlyBase records into one gene (called alphaE7, although the symbol Ali has priority it seems better to keep this more 'systematic' name and symbol): Ali, Est-23, Mce. Many thanks Subject: Re: esterase queries Dear Dr Ashburner I will put my replies under your queries: > >1. You say that alphaE7 is 84D3-10; fine, but the others in this cluster >are at 84D3, is that OK ? Not exactly. The original YAC clone containing the cluster maps to 84D3-10 by in situ hybridisation. We do not know exactly where in that 300kb the cluster is situated, so the best position we have for the 10 genes we have identified from that YAC clone is 84D3-10. > >2. I have merged the following three FlyBase records into one gene (called >alphaE7, although the symbol Ali has priority it seems better to keep >this more 'systematic' name and symbol): Ali, Est-23, Mce. Agreed. > >Thanks and regards, Robyn ______________________________________ Robyn Russell, Principal Research Scientist Biotechnology Program, CSIRO Division of Entomology GPO Box 1700 CANBERRA ACT 2601 AUSTRALIA ___________________________________
