Spermatozoa of Sminthopsis murina (Mammalia: Metatheria) exhibit an unusually high degree of chromatin stability in the absence of disulphide bonding in protamine 1

Johnston, S. D., López-Fernández, C., Arroyo, F., Fardell, S., Roy, R. and Gosálvez, J. (2015) Spermatozoa of Sminthopsis murina (Mammalia: Metatheria) exhibit an unusually high degree of chromatin stability in the absence of disulphide bonding in protamine 1. Reproduction, Fertility and Development, 28 9: 1268-1275. doi:10.1071/RD14504

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Author Johnston, S. D.
López-Fernández, C.
Arroyo, F.
Fardell, S.
Roy, R.
Gosálvez, J.
Title Spermatozoa of Sminthopsis murina (Mammalia: Metatheria) exhibit an unusually high degree of chromatin stability in the absence of disulphide bonding in protamine 1
Formatted title
Spermatozoa of Sminthopsis murina (Mammalia: Metatheria) exhibit an unusually high degree of chromatin stability in the absence of disulphide bonding in protamine 1
Journal name Reproduction, Fertility and Development   Check publisher's open access policy
ISSN 1031-3613
1448-5990
Publication date 2015-02-25
Sub-type Article (original research)
DOI 10.1071/RD14504
Open Access Status Not yet assessed
Volume 28
Issue 9
Start page 1268
End page 1275
Total pages 8
Place of publication Clayton, VIC, Australia
Publisher C S I R O Publishing
Collection year 2016
Language eng
Formatted abstract
Although all but a single genus (Planigale) of the metatheria so far examined contain no cysteine residues in protamine 1, we report a remarkable level of chromatin stability in the spermatozoa of the common dunnart, Sminthopsis murina. S. murina cauda epididymal spermatozoa and somatic epithelial cells were exposed to a combination of graded treatments to lyse sperm protein and induce sperm DNA damage via standard freeze–thaw protocols and post-thaw incubation at 37°C for 48 h, exposure to sodium nitroprusside (SNP) and the enzyme AluI restriction endonuclease. Sperm DNA fragmentation was assessed using the comet assay and sperm chromatin dispersal test. Although S. murina somatic cells showed DNA fragmentation following protein lysis and after treatment with all the protocols specifically designed to induce chromatin damage, sperm DNA fragmentation was only observed following moderate to severe proteolytic exposure and treatment with the restriction endonuclease; there was also an increase in the baseline halo of spermatozoa treated with an aggressive reducing agent, but no corresponding evidence of fragmented DNA, suggesting that cysteine residues may be functioning to conform tertiary and/or quaternary chromatin structure. Given that the protamine 1 of S. murina contains no cysteine, we suggest that the source of these residues is possibly the histone fraction of the chromatin and that the high level of stability is potentially related to prolonged sperm survival in the female’s reproductive tract.
Keyword Cysteine residues
Halomax
Marsupial
Sperm chromatin dispersion assay
Sperm DNA fragmentation
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Agriculture and Food Sciences
Official 2016 Collection
 
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Created: Mon, 03 Aug 2015, 06:27:09 EST by Associate Professor Stephen Johnston on behalf of School of Agriculture and Food Sciences