Genomic Structure, Evolutionary Origins, and Reproductive Function of a Large Amplified Intrinsically Disordered Protein-Coding Gene on the X Chromosome (Laidx) in Mice. Issue 6 (1st June 2020)

• Record Type: Journal Article
• Authors: Arlt, Martin F; Brogley, Michele A; Stark-Dykema, Evan R; Hu, Yueh-Chiang; Mueller, Jacob L
• Is Part Of: G3. Volume 10:Issue 6(2020)
• Page Start: 1997
• Page End: 2005
• Publication Date: 2020-06-01
• Subjects: amplicon -- X chromosome -- horizontal gene transfer -- male fertility -- testicular germ cells -- mouse -- Genetics of Sex; Genetics -- Research -- Periodicals; Genomics -- Periodicals; Genetics; Genomics; Genes; Genetics -- Research; Genomics; Electronic journals; Periodical; Periodicals; Fulltext; Internet Resources; Periodicals; 572.8
• DOI: 10.1534/g3.120.401221
• Languages: English
• ISSNs: 2160-1836

Abstract

Abstract: Mouse sex chromosomes are enriched for co-amplified gene families, present in tens to hundreds of copies. Co-amplification of Slx / Slxl1 on the X chromosome and Sly on the Y chromosome are involved in dose-dependent meiotic drive, however the role of other co-amplified genes remains poorly understood. Here we demonstrate that the co-amplified gene family on the X chromosome, Srsx, along with two additional partial gene annotations, is actually part of a larger transcription unit, which we name Laidx . Laidx is harbored in a 229 kb amplicon that represents the ancestral state as compared to a 525 kb Y-amplicon containing the rearranged Laidy . Laidx contains a 25, 011 nucleotide open reading frame, predominantly expressed in round spermatids, predicted to encode an 871 kD protein. Laidx has orthologous copies with the rat and also the 825-MY diverged parasitic Chinese liver fluke, Clonorchis sinensis, the likely result of a horizontal gene transfer of rodent Laidx to an ancestor of the liver fluke. To assess the male reproductive functions of Laidx, we generated mice carrying a multi-megabase deletion of the Laidx -ampliconic region. Laidx -deficient male mice do not show detectable reproductive defects in fertility, fecundity, testis histology, and offspring sex ratio. We speculate that Laidx and Laidy represent a now inactive X vs. Y chromosome conflict that occurred in an ancestor of present day mice.