RPS5

RPS5 (PF3D7_API02300) is a small-subunit ribosomal protein gene encoded on the 35 kb plastid-like (apicoplast) DNA circle of Plasmodium falciparum, identified as one of a set of 17 ribosomal protein genes in the complete gene map of this organellar genome, and transcribed from a polycistronic locus (PMID:8757284). The polycistronic transcripts that include the RPS5-containing operon undergo RNA processing through excision of tRNA molecules at sites associated with a conserved sequence motif, with antisense transcripts across the same loci processed at identical positions (PMID:27458998). Beyond its membership in the apicoplast ribosome and this transcript-level processing context, no direct functional or structural mechanistic data have been established for RPS5 in the available corpus; the protein is not individually distinguished from other apicoplast ribosomal protein genes in the processing analysis (PMID:27458998).

1. 1996 Medium

   Before this work it was unknown which ribosomal protein genes the apicoplast genome carries; complete mapping placed RPS5 on the 35 kb DNA circle, establishing it as an organelle-encoded component of the apicoplast translational machinery.

   Evidence Complete gene mapping and sequence analysis of the 35 kb apicoplast DNA circle in P. falciparum

   PMID:8757284

   Open questions at the time

   • No evidence that the RPS5 gene product is expressed as a protein or assembled into a ribosome
   • No functional or structural characterization of RPS5 individually
   • Polycistronic organization inferred at the genome level, not resolved for the RPS5 transcript specifically
2. 2016 Low

   It was unclear how the apicoplast polycistronic transcripts are matured; transcript analysis showed that tRNA excision at a conserved motif processes the operons containing RPS5, defining the RNA-processing context of the locus.

   Evidence RNA transcript analysis with RT-PCR and sequencing of apicoplast transcripts, identifying processing sites in P. falciparum

   PMID:27458998

   Open questions at the time

   • RPS5 is not individually distinguished from other ribosomal protein genes in this transcript-level analysis
   • Does not establish RPS5 protein levels, translation, or ribosome assembly
   • The enzyme(s) mediating tRNA excision at these sites are not identified

• Whether RPS5 protein is expressed, incorporated into the apicoplast small ribosomal subunit, and required for organelle translation or parasite viability remains uncharacterized in the available corpus.
• No direct evidence of RPS5 protein expression or ribosome incorporation
• No genetic knockout, knockdown, or essentiality data for RPS5
• No structural model or interaction partners defined for the RPS5 protein