Identification of novel Y chromosome encoded transcripts by testis transcriptome analysis of mice with deletions of the Y chromosome long arm.
BACKGROUND
The male-specific region of the mouse Y chromosome long arm (MSYq) is comprised largely of repeated DNA, including multiple copies of the spermatid-expressed Ssty gene family. Large deletions of MSYq are associated with sperm head defects for which Ssty deficiency has been presumed to be responsible.


RESULTS
In a search for further candidate genes associated with these defects we analyzed changes in the testis transcriptome resulting from MSYq deletions, using testis cDNA microarrays. This approach, aided by accumulating mouse MSYq sequence information, identified transcripts derived from two further spermatid-expressed multicopy MSYq gene families; like Ssty, each of these new MSYq gene families has multicopy relatives on the X chromosome. The Sly family encodes a protein with homology to the chromatin-associated proteins XLR and XMR that are encoded by the X chromosomal relatives. The second MSYq gene family was identified because the transcripts hybridized to a microarrayed X chromosome-encoded testis cDNA. The X loci ('Astx') encoding this cDNA had 92-94% sequence identity to over 100 putative Y loci ('Asty') across exons and introns; only low level Asty transcription was detected. More strongly transcribed recombinant loci were identified that included Asty exons 2-4 preceded by Ssty1 exons 1, 2 and part of exon 3. Transcription from the Ssty1 promotor generated spermatid-specific transcripts that, in addition to the variable inclusion of Ssty1 and Asty exons, included additional exons because of the serendipitous presence of splice sites further downstream.


CONCLUSIONS
We identified further MSYq-encoded transcripts expressed in spermatids and deriving from multicopy Y genes, deficiency of which may underlie the defects in sperm development associated with MSYq deletions.
Touré
Aminata
A
Division of Developmental Genetics, MRC National Institute for Medical Research, Mill Hill, London, NW7 1AA, UK. toure@cochin.inserm.fr
Clemente
Emily J
EJ
Ellis
Peter
P
Mahadevaiah
Shantha K
SK
Ojarikre
Obah A
OA
Ball
Penny A F
PA
Reynard
Louise
L
Loveland
Kate L
KL
Burgoyne
Paul S
PS
Affara
Nabeel A
NA
D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics; D033942:Adaptor Proteins, Vesicular Transport; D000595:Amino Acid Sequence; D000818:Animals; D002868:Chromosomal Proteins, Non-Histone / Q000737:chemistry / Q000235:genetics; D002872:Chromosome Deletion; D033481:Chromosomes, Mammalian / Q000235:genetics*; D005091:Exons / Q000235:genetics; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D007438:Introns / Q000235:genetics; D008297:Male; D051379:Mice; D046228:Microarray Analysis; D008969:Molecular Sequence Data; D010802:Phylogeny; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D013087:Spermatids / Q000378:metabolism; D013091:Spermatogenesis / Q000235:genetics; D013737:Testis / Q000378:metabolism*; D014158:Transcription, Genetic / Q000235:genetics*; D014960:X Chromosome / Q000235:genetics; D014998:Y Chromosome / Q000235:genetics*
D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; D002868:Chromosomal Proteins, Non-Histone; D012333:RNA, Messenger; C506091:SLY1 protein, mouse