Disease relevance of RPL21

• During systematic analysis of the mRNAs expressed in a human colorectal carcinoma with the aim of evidencing new makers of the disease (Frigerio et al. (1995), in press), we isolated several clones corresponding to homologs of rat ribosomal protein mRNAs L5, L21, L27a, L28, S5, S9, S10 and S29 [1].

High impact information on RPL21

• Subpopulations of chloroplast ribosomes change during photoregulated development of Zea mays leaves: ribosomal proteins L2, L21, and L29 [2].
• However, L21 is present about equally in plastid ribosomes of unilluminated and illuminated seedlings [2].
• Preliminary results indicate that presence of conserved sequences within the rpl21 and rps1 promoter regions which compete for the same DNA binding activities [3].
• We have developed a monoclonal antibody (L21) that strongly agglutinates all erythrocytes except In(Lu), and we have identified eight In(Lu) individuals among 42,000 blood donors tested [4].
• This ranges from 145 pseudogenes for RPL21 down to 3 pseudogenes for RPL14 [5].

Biological context of RPL21

• We have chosen the previously characterised RPL21 gene encoding plastid-localised ribosomal proteins RPL21, to analyse activation of gene expression during germination [6].
• We describe the purification and characterization of the spinach chloroplast ribosomal protein L21 and the isolation and nucleotide sequence of a cDNA clone that encodes its cytoplasmic precursor [7].
• Relative to L22 ewes, L21 and H22 ewes had lower worm burdens, parasite per capita fecundity and in vitro establishment rates of both T. circumcincta and Haemonchus contortus [8].
• Phorbol ester induction of differentiation and apoptosis in the K562 cell line is accompanied by marked decreases in the stability of globin mRNAs and decreases in the steady state level of mRNAs encoding for ribosomal proteins L35, L31, L27, and L21 [9].

Anatomical context of RPL21

• The use of L21 and similar monoclonal antibodies provides a more sensitive means of detecting In(Lu) erythrocytes than typing with human anti-Lub antisera [4].
• L21 reacted weakly with peripheral monocytes and granulocytes but not other normal peripheral blood cells [10].
• Mucosal mast cell and eosinophil counts were similar for all ewes, but H22 ewes had higher globule leukocyte counts than L22 and L21 ewes [8].

Associations of RPL21 with chemical compounds

• The cDNA clone also encodes a 55-residue long transit peptide (with a high proportion of the polar residues, threonine and serine), to target the L21 protein into chloroplasts [7].
• Inhibition of most of the expression of the cysteine proteinases of Entamoeba histolytica strain HM-1:IMSS was successfully performed by transcription of ehcp5 antisense RNA using the promoter of ehg34, which encodes a L21 ribosomal protein of E. histolytica [11].
• About 90% of recent isolates belonged to type L21, indicating the spread of a specific type of MRSA in Japan. Of the type L21 strains, 41.9% included the aac(6')/aph(2") gene, which was one of the risk factors of arbekacin (ABK) resistance, but only 5.5% were resistant to ABK [12].

Other interactions of RPL21

• An L21 ribosomal protein pseudogene is embedded in BRCA1 intron 13 [13].
• The most abundant were copies of genes encoding keratin 18, glyceraldehyde-3-phosphate dehydrogenase and ribosomal protein L21 [14].
• Using microarray analysis and quantitative RT-polymerase chain reaction, we found an increase in c-myc-regulated gene expression including an induction of ribosomal subunit messenger RNA's (RPS 10, RPL 21) and rRNA (18S) [15].

Analytical, diagnostic and therapeutic context of RPL21

• From partial sequence analysis, two cDNAs were shown to code for the ribosomal (r-) proteins, simian L44 and human L21, and the others were shown to be new [16].
• SDS-PAGE analyses of the L21 immunoprecipitate under non-reducing conditions revealed a single band of 61,000 MW, while two bands of 46,000 and 49,000 MW were detected under reducing conditions [10].

References