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Mol Cytogenet. 2014 Jul 1;7:45. doi: 10.1186/1755-8166-7-45. eCollection 2014.

Meiotic prophase I defects in an oligospermic man with Wolf-Hirschhorn syndrome with ring chromosome 4.

Yao Q#1, Wang L#2, Yao B#1, Gao H#3, Li W3, Xia X3, Shi Q2, Cui Y3.

Author information

1
Institute of Reproductive Medicine, Jinling Hospital, Nanjing University School of Medicine, 305 East Zhongshan Road, Nanjing 210002, PR China.
2
Laboratory of Molecular and Cell Genetics, Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, China.
3
Institute of Laboratory Medicine, Jinling Hospital, Nanjing University School of Medicine, 305 East Zhongshan Road, Nanjing 210002, PR China.
#
Contributed equally

Abstract

BACKGROUND:

Ring chromosomes are often associated with spermatogenetic failure. However, the mechanism is poorly understood. We here reported a single man with severe oligospermia and a ring chromosome 4 with a microdeletion at 4p16.3.

RESULTS:

Synapsis (as SCP3), recombination (as MLH1) and transcriptional inactivation (as BRCA1) in a testicular biopsy were examined by fluorescence immunostaining. In the oligospermia patient, 35.4% of spermatocytes were in zygotene phase compared with 5.2% in controls. The patient had a significantly reduced recombination frequency with mean of 45.9 MLH1 foci/cell compared with 47.8 in controls. In the patient, chromosome 4 in all pachytene cells displayed loop formation with varying degrees of unpaired regions. BRCA1 localized along asynapsed regions regardless of XY body association.

CONCLUSIONS:

Ring chromosome 4 might affect the progression of meiosis I prophase, synapse formation, and transcriptional activation of asynapsed areas, and impair male fertility.

KEYWORDS:

Oligospermia; Recombination; Ring chromosome 4; Synapse complex; Transcriptional inactivation

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