Characterization of two distinct gene transcripts for ribosomal protein L21 from pathogenic and nonpathogenic strains of Entamoeba histolytica.
A second gene (rp-L21) copy, clone g34, coding for ribosomal (r-) protein L21, was isolated from the pathogenic (P) strain HM-1:IMSS cl6 of the intestinal parasite Entamoeba histolytica (Eh). The gene was compared to the previously isolated copy, gLE3 [Petter et al., Mol. Biochem. Parasitol. 56 (1992) 329-334], with respect to its primary structure, mRNA levels and binding to the r-complex during translation. Unlike the gLE3 gene copy [Petter et al., Mol. Biochem. Parasitol. 56 (1992) 329-334], g34 was found not to be physically connected to an actin gene copy. Homologous copies of the two rp-L21 genes were also characterized from the nonpathogenic (NP) strain SAW1734R clAR, as well as from its P derivative. Sequence comparison of the coding regions of the two rp-L21 revealed almost full identity. Significant differences were found, however, within their 3' and 5' flanking regions. Using the 3' rapid amplification of cDNA ends (3' RACE) method [Frohman et al., Proc. Natl. Acad. Sci. USA 85 (1988) 8998-9002], as well as Northern and slot blot hybridizations, it was demonstrated that both rp-L21 mRNAs are found in similar amounts. However, as was shown by differential hybridization, the relative binding of each transcript to the r-complex varied somewhat between P and NP strains. This finding suggests that the control of expression of rp-L21 in Eh may involve regulation at the post-transcriptional level.
Department of Membrane Research and Biophysics, Weizmann Institute of Science, Rehovot, Israel.
R
R
Petter
S
S
Moshitch
S
S
Rozenblatt
Y
Y
Nuchamowitz
D
D
Mirelman
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D016054:DNA, Protozoan; D004748:Entamoeba histolytica / Q000235:genetics* / Q000472:pathogenicity; D017125:Genes, Protozoan; D008969:Molecular Sequence Data; D015800:Protozoan Proteins / Q000235:genetics*; D012333:RNA, Messenger / Q000378:metabolism; D016053:RNA, Protozoan / Q000378:metabolism; D012269:Ribosomal Proteins / Q000235:genetics*; D016415:Sequence Alignment
D016054:DNA, Protozoan; D015800:Protozoan Proteins; D012333:RNA, Messenger; D016053:RNA, Protozoan; D012269:Ribosomal Proteins; C060232:ribosomal protein L21