An expanded mouse testis transcriptome and mass spectrometry defines novel proteins

Area of Science:

• Genomics
• Molecular Biology
• Reproductive Biology

Background:

• The testis transcriptome is highly complex, but previous analyses using reductive methods underestimated its full extent.
• A comprehensive understanding of the testis transcriptome is crucial for reproductive biology research.

Purpose of the Study:

• To generate a more complete testis transcriptome by integrating reductive and combinatorial transcript-building approaches.
• To characterize novel transcripts, their expression patterns, and protein-coding potential within the testis.

Main Methods:

• Combined Tuxedo (reductive) and spliced-RUM (combinatorial) methods for transcript identification.
• Analyzed transcript expression across different tissues and cell types.
• Assessed protein-coding potential of novel transcripts using bioinformatic tools and shotgun mass spectrometry.

Main Results:

• The expanded testis transcriptome includes 42% unannotated RNAs, with novel isoforms and novel genes comprising the majority of newly discovered transcripts.
• Novel transcripts are predominantly testis-specific, with novel isoforms also found in the adult ovary.
• Novel genes are mainly expressed in meiotic and post-meiotic germ cells, and a subset exhibits significant protein-coding potential, confirmed by mass spectrometry.

Conclusions:

• The testis transcriptome is more complex than previously recognized, with a substantial proportion of unannotated and novel transcripts.
• These novel transcripts, including those with protein-coding potential, contribute to the unique proteome of the testis.
• This work provides a more comprehensive view of the testis transcriptome, essential for understanding male reproductive function.