The uptake of radioactive aminoacids by spermatozoa. The intracellular site of incorporation into proteins


Regional Research Laboratory, Hyderabad-9, India

Published in: Biochemical Journal, 1963, 86, 308-313.


It has been shown that bull semen and washed spermatozoa can incorporate radioactive amino acids into their proteins in spite of the absence of any chemically detectable RNA in the spermatozoa (Bhargava, 1957; Bhargava,-Bishop & Work, 1959; Martin & Brachet, 1959). We have obtained evidence for the presence of a small amount of metabolically active RNA in bovine spermatozoa (Abraham & Bhargava, 1963); apparently, these spermatozoa can bring about net synthesis of this RNA. If the incorporation of amino acids into the proteins of spermatozoa represents the formation of new protein molecules, it is possible that the information necessary for this synthesis is obtained from the DNA of the cell through this metabolically active RNA; recent work strongly suggests that a special type of RNA, which has a high metabolic activity, is involved in the transfer of hereditary information from DNA to proteins (Gros et al. 1961; Brenner, Jacob & Meselson, 1961). Spermatozoa may thus provide a useful system for a study of the exact mechanism of the transfer of information from DNA to protein, since the dilution of the active RNA that may mediate the transfer with non-active RNA would be much less in this system than is usually obtained in most other systems. In view of the possible importance of protein synthesis by spermatozoa, it was considered desirable to gain further information on the nature of the incorporation of radioactive amino acids into’ the proteins of spermatozoa. In this paper we present evidence that strongly suggests that the above-mentioned incorporation occurs in the acrosomal region of the spermatozoa.

Since so far there have been only two reports on the incorporation of isotopically labelled amino acids into the proteins of spermatozoa, and since both these reports have been confined to bull spermatozoa, it was considered desirable to determine whether other mammalian spermatozoa which contain a normal acrosome, and fowl spermatozoa in which the acrosome is either absent or is strongly modified (P. T, Iype, K. A. Abraham & P.M. Bhargava, unpublished work), are capable of incorporating amino acids into their proteins. We have therefore extended some of the earlier studies, on the incorporation of amino acids into bull spermatozoa, to buffalo, goat and cock spermatozoa; the spermatozoa of buffalo, a species closely related to bull, have been earlier shown to differ from those of bulls in several ways, for example, in their preservability (Perry, 1960). The incorporation of 14C-labelled amino acids into the proteins of buffalo and goat spermatozoa was found to follow the same pattern as is obtained with bull spermatozoa (Bhargava e.t al. 1959), and no significant incorporation was obtained with cock spermatozoa.

PMCID: PMC1201754


The uptake of radioactive aminoacids by spermatozoa. Theintracellular site of incorporation into proteins. K A ABRAHAM & P M BHARGAVA. Biochemical Journal, 1963, 86, 308-313.


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