Transcript Alteration in Leishmania
Recent studies of mitochondrial transcripts, initially in African trypanosomes, have revealed that nucleotides (uridines) not encoded in the genes are added to their transcripts. This transcript alteration is developmentally regulated for some genes, such as the apocytochrome b and cytochrome oxidase II genes, but not others such as MURF2 (Feagin et al., 1987 and 1988; Feagin and Stuart, 1988). In addition, this uridine addition does not occur for all genes. These studies indicate the existence of a genetic regulatory process in Kinetoplastidae unlike any previously described. It has been suggested that the transcript alteration creates initiation codons, corrects frameshifts, and alters the 3′ untranslated regions of transcripts (Benne et al., 1986; Feagin et al., 1987; Feagin and Stuart, 1988). These processes could thus affect the transcript translatability, the nature of the protein product or the stability of the transcripts. In African trypanosomes, where developmental regulation of the production of the mitochondrial respiratory System is apparent (Vickerman, 1985), the transcript alteration process probably plays a role in this regulation. However, little is known about possible developmental regulation of the production of the mitochondrial respiratory System in Leishmania, including those that infect humans (see Blum et al., 1987).
KeywordsCodon Alanine Uridine Hemin Leishmaniasis
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