M. Soto et al., GENOMIC ORGANIZATION AND EXPRESSION OF 2 INDEPENDENT GENE ARRAYS CODING FOR 2 ANTIGENIC ACIDIC RIBOSOMAL-PROTEINS OF LEISHMANIA, The Journal of biological chemistry, 268(29), 1993, pp. 21835-21843
In the present paper we describe the isolation and characterization of
four novel genes of the parasitic protozoan Leishmania infantum. Thes
e genes are organized as two independent gene clusters, and they are r
elated by nucleotide sequence to eukaryotic genes encoding acidic ribo
somal proteins. Each gene cluster contains two tandemly linked genes c
oding for identical proteins. Each of the proteins coded by the gene c
lusters (called LiP and LiP') are highly divergent in sequence, showin
g the characteristic features of eukaryotic P-proteins from the P2 gro
up. In spite of the sequence conservation of the coding regions of eac
h of the genes in the cluster, the 5'- and 3'-untranslated regions are
heterogeneous in sequence. The analysis of the expression of these ge
nes indicates that logarithmic phase promastigotes show increased leve
ls of LiP- and LiP'-specific transcripts compared with stationary phas
e promastigotes. The steady state RNA levels of the LiP and LiP' genes
show a similar dependence of the growth phase of the parasite. Using
specific probes for the divergent 3'-untranslated regions of each of t
he genes, it was found that the abundance of the mature transcripts is
different even when the transcripts are derived from the same gene cl
uster. These findings probably indicate that the 3'-untranslated regio
ns may influence the stability or turnover of the transcripts derived
from both LiP and LiP' gene clusters.