RPL10L

RPL10L is a testis-specific autosomal retrogene of the X-linked ribosomal protein RPL10 that compensates for meiotic sex chromosome inactivation (MSCI)-mediated silencing of RPL10 during male meiosis, thereby sustaining ribosome biogenesis in late-prophase spermatocytes (PMID:28502657, PMID:12490704). Loss of Rpl10l in mice disrupts ribosome biogenesis and blocks the prophase-to-metaphase transition of meiosis I, causing male infertility; this phenotype is rescued by transgenic expression of Rpl10 from the Rpl10l promoter, establishing functional interchangeability between the two paralogs (PMID:28502657). A homozygous missense variant in RPL10L (p.H86P) that reduces protein levels co-segregates with severe oligozoospermia in an infertile consanguineous family, linking RPL10L to human male infertility (PMID:32111475).

1. 2002 Medium

   Identifying RPL10L as an intronless autosomal retrogene of X-linked RPL10 with testis-restricted expression established the hypothesis that it compensates for X-chromosome gene dosage reduction during spermatogenesis.

   Evidence Northern blot, PCR, and sequence analysis of human RPL10L locus

   PMID:12490704

   Open questions at the time

   • No functional evidence that RPL10L protein is incorporated into ribosomes
   • Compensation hypothesis untested by loss-of-function experiments
2. 2009 Low

   Detection of RPL10L transcript in ovarian tissue challenged the view that expression is strictly testis-limited, raising questions about broader roles.

   Evidence End-point PCR on normal ovarian and ovarian cancer tissue

   PMID:19333399

   Open questions at the time

   • Single PCR method without quantification or protein-level validation
   • No functional consequence of ovarian expression demonstrated
   • Not independently replicated
3. 2017 High

   Knockout and rescue experiments proved that RPL10L is essential for ribosome biogenesis during male meiotic prophase and functionally replaces RPL10 silenced by MSCI, resolving the central mechanistic question of why an autosomal ribosomal protein retrogene is needed for spermatogenesis.

   Evidence Rpl10l knockout mouse, transgenic Rpl10 rescue driven by Rpl10l promoter, ectopic RPL10L expression in RPL10-deficient somatic cells

   PMID:28502657

   Open questions at the time

   • Structural basis for RPL10L incorporation into ribosomes not determined
   • Whether RPL10L-containing ribosomes have altered translational properties is unknown
4. 2020 Medium

   A human loss-of-function variant in RPL10L co-segregating with oligozoospermia extended the mouse findings to human male infertility, providing genetic evidence for clinical relevance.

   Evidence Whole-exome sequencing in consanguineous family, in vitro protein expression assay

   PMID:32111475

   Open questions at the time

   • Single family studied; broader allelic spectrum in infertile men unknown
   • Variant effect on ribosome assembly not tested in spermatocytes

• Whether RPL10L-containing ribosomes have specialized translational activity distinct from RPL10-containing ribosomes, and whether RPL10L functions outside spermatogenesis (e.g., in ovary), remain unresolved.
• No ribosome profiling or structural studies of RPL10L-containing ribosomes
• Functional significance of ovarian expression not tested
• Translational targets specific to RPL10L-ribosomes in spermatocytes unknown