Linking spermatid ribonucleic acid (RNA) binding protein and retrogene diversity to reproductive success.
Spermiogenesis is a postmeiotic process that drives development of round spermatids into fully elongated spermatozoa. Spermatid elongation is largely controlled post-transcriptionally after global silencing of mRNA synthesis from the haploid genome. Here, rats that differentially express EGFP from a lentiviral transgene during early and late steps of spermiogenesis were used to flow sort fractions of round and elongating spermatids. Mass-spectral analysis of 2D gel protein spots enriched >3-fold in each fraction revealed a heterogeneous RNA binding proteome (hnRNPA2/b1, hnRNPA3, hnRPDL, hnRNPK, hnRNPL, hnRNPM, PABPC1, PABPC4, PCBP1, PCBP3, PTBP2, PSIP1, RGSL1, RUVBL2, SARNP2, TDRD6, TDRD7) abundantly expressed in round spermatids prior to their elongation. Notably, each protein within this ontology cluster regulates alternative splicing, sub-cellular transport, degradation and/or translational repression of mRNAs. In contrast, elongating spermatid fractions were enriched with glycolytic enzymes, redox enzymes and protein synthesis factors. Retrogene-encoded proteins were over-represented among the most abundant elongating spermatid factors identified. Consistent with these biochemical activities, plus corresponding histological profiles, the identified RNA processing factors are predicted to collectively drive post-transcriptional expression of an alternative exome that fuels finishing steps of sperm maturation and fitness.
Departments of Pharmacology.
Karen M
KM
Chapman
Heather M
HM
Powell
Jaideep
J
Chaudhary
John M
JM
Shelton
James A
JA
Richardson
Timothy E
TE
Richardson
F Kent
FK
Hamra
D000818:Animals; D048430:Cell Shape; D015180:Electrophoresis, Gel, Two-Dimensional; D018507:Gene Expression Regulation, Developmental; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D008297:Male; D008954:Models, Biological; D020543:Proteome / Q000235:genetics / Q000378:metabolism; D040901:Proteomics; D012323:RNA Processing, Post-Transcriptional; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D055647:Rats, Transgenic; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D012261:Ribonucleoproteins / Q000235:genetics / Q000378:metabolism; D013079:Sperm Maturation / Q000235:genetics / Q000502:physiology; D013087:Spermatids / Q000166:cytology / Q000378:metabolism*; D013091:Spermatogenesis / Q000235:genetics / Q000502:physiology
D020543:Proteome; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D011994:Recombinant Proteins; D012261:Ribonucleoproteins; C485184:enhanced green fluorescent protein; C026452:messenger ribonucleoprotein; D049452:Green Fluorescent Proteins