Expression of ribosomal protein L22e family members in Drosophila melanogaster: rpL22-like is differentially expressed and alternatively spliced

Nucleic Acids Res. 2011 Apr;39(7):2701-16. doi: 10.1093/nar/gkq1218. Epub 2010 Dec 7.

Abstract

Several ribosomal protein families contain paralogues whose roles may be equivalent or specialized to include extra-ribosomal functions. RpL22e family members rpL22 and rpL22-like are differentially expressed in Drosophila melanogaster: rpL22-like mRNA is gonad specific whereas rpL22 is expressed ubiquitously, suggesting distinctive paralogue functions. To determine if RpL22-like has a divergent role in gonads, rpL22-like expression was analysed by qRT-PCR and western blots, respectively, showing enrichment of rpL22-like mRNA and a 34 kDa (predicted) protein in testis, but not in ovary. Immunohistochemistry of the reproductive tract corroborated testis-specific expression. RpL22-like detection in 80S/polysome fractions from males establishes a role for this tissue-specific paralogue as a ribosomal component. Unpredictably, expression profiles revealed a low abundant, alternative mRNA variant (designated 'rpL22-like short') that would encode a novel protein lacking the C-terminal ribosomal protein signature but retaining part of the N-terminal domain. This variant results from splicing of a retained intron (defined by non-canonical splice sites) within rpL22-like mRNA. Polysome association and detection of a low abundant 13.5 kDa (predicted) protein in testis extracts suggests variant mRNA translation. Collectively, our data show that alternative splicing of rpL22-like generates structurally distinct protein products: ribosomal component RpL22-like and a novel protein with a role distinct from RpL22-like.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alternative Splicing*
  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Drosophila Proteins / chemistry
  • Drosophila Proteins / genetics*
  • Drosophila Proteins / metabolism
  • Drosophila melanogaster / genetics*
  • Drosophila melanogaster / metabolism
  • Male
  • Molecular Sequence Data
  • Polyribosomes / metabolism
  • Protein Biosynthesis
  • RNA, Messenger / metabolism
  • RNA-Binding Proteins / chemistry
  • Ribosomal Proteins / chemistry
  • Ribosomal Proteins / genetics*
  • Ribosomal Proteins / metabolism
  • Ribosomes / metabolism
  • Sequence Homology, Amino Acid
  • Testis / metabolism

Substances

  • Drosophila Proteins
  • RNA, Messenger
  • RNA-Binding Proteins
  • Ribosomal Proteins
  • RpL22 protein, Drosophila
  • Rpl22-like protein, Drosophila

Associated data

  • GENBANK/HM756190
  • GENBANK/HQ190956