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In patients with betao thalassaemia from Ferrara, beta globin mRNA sequences are either absent or structurally abnormal while in betao thalassaemia in Catania, beta globin mRNA sequences are present. In deltabeta thalassaemia there is a deletion of beta-like globin genes, while in betao Catania DNA, no beta globin gene deletion is detectable.

A 9 to 10-S messenger RNA was purified from duck immature erythrocyte polyribosomes and found to direct the synthesis of several duck globin chains in a rabbit reticulocyte-lysate protein-synthesising system. The ability to compete with the endogenous rabbit globin mRNA was, however, very low. On the other hand, rabbit 9-s RNA, when put into a duck immature erythrocyte-lysate cell-free system, was translated with high efficiency, effectively depressing the translation of the endogenous duck mRNA.These experiments lead us to conclude that between duck and rabbit messengers there are fundamental differences in the RNA structure a t or near the initiation sites leading to their respective abilities to be recognised and translated with different efficiencies in cell-free systems.During studies concerning the synthesis, processing and function of messenger RNA in eukaryote cells 123-251, we have prepared and purified an RNA with a sedimentation coefficient of about 9 to 10 S from polyribosomes of immature duck erythrocytes [l]. We wished to show that this RNA contained the message for duck haemoglobins, by virtue of its ability to be translated in a cell-free system. Concerning the choice of such a system, there have appeared a number of reports describing the use of rabbit or other mammalian reticulocyte lysates as a cell-free system which will translate added messenger RNAs [2-61. I n this paper we show that, Uskg a rabbit reticulocyte cell-frek system, the duck 9-S RNA is translated into polypeptides which correspond chromatographically to all of the duck globins. Furthermore, we describe how duck mRNA ls less translatable than a rabbit haemoglobin message in both rabbit and duck immature erythrocyte cell-free systems. Possible reasons for this qualitative difference between two messengers in regard to translation efficiency will be discussed. MATERIAL AND METHODS ChemicalsSucrose (RNAase-free) was obtained from Mann Research Laboratories (U.S.A.), sodium deoxychelate from Fluka, ATP, GTP, creatine phosphate . Definition. A,,, unit, the quantity of material contained ln 1 ml of a solution which has an absorbance of 1 at nm, when measured in a 1-cm path-length cell. Animals Peking ducks and White Kunath rabbits were used. TO induce anaemia, the ducks were given three daily subcutaneous injections of 1.5 acetylphenylhydrazine (15 mg/kg body weight), and the anaemia was maintained by bleeding the animals from the jugular vein during the following two days using heparin as an anti-coagulant. The rabbits were injected with the same dose for four days and blood was taken by heart puncture on the 6th or 7th day. Cell Fractionation and Isolation of Messenger RNA Duck or rabbit immature red blood cells were isolated and washed free of plasma as described by Solutions

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