Mutations of t-complex testis expressed gene 5 transcripts in the testis of sterile t-haplotype mutant mouse.
OBJECTIVE
To determine the possible roles of the t-complex testis expressed gene 5 (Tctex5) on sperm functions, the full-length sequence of mRNA was studied and compared in the testis between the normal wild-type and the sterile t-haplotype mutant mice.


METHODS
We applied rapid amplification of cDNA ends, Northern blot and reverse transcription polymerase chain reaction to analyze the full length of Tctex5 mRNAs isolated from testes of the wild-type and the t-haplotype mice. Reverse transcription polymerase chain reaction was used to semi-quantitatively compare expression of Tctex5 transcripts in the 16 tissues and 9.5 day stage embryos in the wild-type mice. E-translation was applied to estimate the amino acid sequences.


RESULTS
One long and one short transcript of Tctex5 mRNA were discovered in mouse testis of wild-type (Tctex5(long-+) and Tctex5(short-+)) and t-haplotype (Tctex5(long-t) and Tctex5(short-t)) mice, respectively. Being enhanced only in the testis, Tctex5(long-t) had 17 point mutations and one 15-bp-deletion in the exon 1 region, comparing with the Tctex5(long-+), whereas the Tctex5(short-t) was similar to the Tctex5(short-+). The short isoforms of Tctex5 mRNAs in the two models encoded exactly the same peptides, but the long isoforms did not. The estimated peptide encoded by Tctex5(long-t) had significant mutations on putative sites of phosphorylation and PP1 binding.


CONCLUSIONS
We established that mutations that occur in the Tctex5 long transcript of the t-haplotype mice are important for normal sperm function, whereas the short transcript of Tctex5 might have a conserved function among different tissues.
Han
Yibing
Y
Department of Obstetrics and Gynaecology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, China. ybhan@cuhk.edu.hk
Song
Xue-Xiong
XX
Feng
Huai-Liang
HL
Cheung
Che-Kwok
CK
Lam
Po-Mui
PM
Wang
Chi-Chiu
CC
Haines
Christophe John
CJ
D000818:Animals; D015870:Gene Expression; D006239:Haplotypes; D007248:Infertility, Male; D008297:Male; D051379:Mice; D008869:Microtubule-Associated Proteins / Q000737:chemistry* / Q000235:genetics*; D009154:Mutation; D009687:Nuclear Proteins / Q000737:chemistry* / Q000235:genetics*; D054645:Protein Phosphatase 1; D020539:Sequence Analysis, Protein; D013094:Spermatozoa / Q000378:metabolism*; D013737:Testis / Q000378:metabolism*; D044767:Ubiquitin-Protein Ligases; D056427:t-Complex Genome Region
D008869:Microtubule-Associated Proteins; D009687:Nuclear Proteins; C533391:Ppp1r11 protein, mouse; D044767:Ubiquitin-Protein Ligases; D054645:Protein Phosphatase 1