Etiopathology of male infertility is highly complex and chromosome rearrangements play an important role in non-obstructive azoospermia (NOA). Testes is the unique organ, where, spermatogenesis regulates the prolifera...Etiopathology of male infertility is highly complex and chromosome rearrangements play an important role in non-obstructive azoospermia (NOA). Testes is the unique organ, where, spermatogenesis regulates the proliferation of germ cells and non-germinal cells (Sertoli cells & Leydig cells) work together in a synchronized fashion. Infertility is a genetic phenomenon and a variety of structural and numerical chromosome aberrations are well known to interfere with male infertility. The role of SycpT657C gene polymorphism has been poorly documented in the Indian population with special reference to non-obstructive azoospermic (NOA) cases. The present study has been designed with the aim to evaluate the following: 1) Cytogenetics study for evaluating the frequency of both structural and numerical chromosome variations in (NOA) cases by short-term peripheral blood lymphocyte (PBL) cultures;2) Genetic heterogenicity of the Sycp3 gene polymorphism by evaluating the frequency of T/C alleles. PCR-based analysis was carried out to characterize bands on agarose gel after ethidium bromide staining and bands were visualized on Gel-Doc system. Karyotype showing two new loci involving chromatid breaks 46,XY2q34, and 46,XY4q32 with the loss of DNA fragment of > 8.0 Mbp. Difference in the frequency of Robertsonian translocation (20%) and mosaicism (46,XY/47,XYY) were observed in the same karyotype. SYCP3 polymorphism shows significant changes in the frequency of TT genotype (43.33%) in homozygous conditions (wild type) and the calculated value of odd ratio (0.23) with a confidence interval varying from 0.08 - 0.71, suggesting an increased risk of developing infertility. To enhance the power of significance, two genotypes were combined together CC + TC which again showed significance with respect to controls. Data of the present study concludes that genetic heterogenicity of Sycp3 gene polymorphism and chromosomal aberrations with loss of DNA (8 Mbp) together confirm of developing risk of infertility in the NOA population.展开更多
Objective:To determine the expression of the synaptonemal complex protein-3 (SYCP3) gene in men with nonobstructive azoospermia. Design:Cross-sectional case study. Setting:Avesina Infertility Clinic,Tehran,Iran. Patie...Objective:To determine the expression of the synaptonemal complex protein-3 (SYCP3) gene in men with nonobstructive azoospermia. Design:Cross-sectional case study. Setting:Avesina Infertility Clinic,Tehran,Iran. Patient(s):One hundred and ten consecutive infertile men presenting nonobstructive azoospermia. Intervention(s):Testicular biopsies for histopathological assessment and analyses of SYCP3 expression level by semiquantitative nested reverse transcription-polymerase chain reaction (RT-PCR). The SYCP3 levels were normalized to expression of the housekeeping phosphoglucomutase 1 gene. Main Outcome Measure(s):Expression of SYCP3 messenger ribonucleic acid (mRNA). Correlation of the histopathological findings with SYCP3 expression levels. Results(s):Testicular SYCP3 mRNA expression was observed in 67/110 (60.9%) patients. The expression level correlated with the degree of spermatogenic failure. Although it was expressed in patients with spermatogenesis and maturation arrest,a lack of expression was seen in all of those men with spermatogonial arrest,Sertoli cell-only syndrome,and testicular atrophy. Conclusion(s):These data indicate that SYCP3 is expressed in human testis and is restricted to germ cells. Our findings,in association with those obtained in experimental animals,shows that lack of SYCP3 expression in human testis may have a negative effect on spermatogenesis and male fertility.展开更多
Background: Meiotic recombination is an important source of genetic variability.Studies on mammals demonstrate a substantial interspecies variation in overall recombination rate, which is dependent mainly on chromosom...Background: Meiotic recombination is an important source of genetic variability.Studies on mammals demonstrate a substantial interspecies variation in overall recombination rate, which is dependent mainly on chromosome(2 n) and chromosome arm number(FN).Bird karyotypes are very conservative with 2 n being about 78–82 and FN being 80–90 in most species.However, some families such as Apodidae(swifts) and Falconidae(falcons) show a substantial karyotypic variation.In this study, we describe the somatic and pachytene karyotypes of the male Common Swift(Apus apus) and the pachytene karyotype of the male Eurasian Hobby(Falco subbuteo) and estimate the overall number and distribution of recombination events along the chromosomes of these species.Methods: The somatic karyotype was examined in bone marrow cells.Pachytene chromosome spreads were prepared from spermatocytes of adult males.Synaptonemal complexes and mature recombination nodules were visualized with antibodies to SYCP3 and MLH1 proteins correspondingly.Results: The karyotype of the Common Swift consists of three metacentric, three submetacentric and two telocentric macrochromosomes and 31 telocentric microchromosomes(2 n = 78; FN = 90).It differs from the karyotypes of related Apodidae species described previously.The karyotype of the Eurasian Hobby contains one metacentric and 13 telocentric macrochromosomes and one metacentric and ten telocentric microchromosomes(2 n = 50; FN = 54) and is similar to that described previously in 2 n, but differs for macrochromosome morphology.Despite an about 40% difference in 2 n and FN, these species have almost the same number of recombination nodules per genome: 51.4 ± 4.3 in the swift and 51.1 ± 6.7 in the hobby.The distribution of the recombination nodules along the macrochromosomes was extremely polarized in the Common Swift and was rather even in the Eurasian Hobby.Conclusions: This study adds two more species to the short list of birds in which the number and distribution of recombination nodules have been examined.Our data confirm that recombination rate in birds is substantially higher than that in mammals, but shows rather a low interspecies variability.Even a substantial reduction in chromosome number does not lead to any substantial decrease in recombination rate.More data from different taxa are required to draw statistically supported conclusions about the evolution of recombination in birds.展开更多
文摘Etiopathology of male infertility is highly complex and chromosome rearrangements play an important role in non-obstructive azoospermia (NOA). Testes is the unique organ, where, spermatogenesis regulates the proliferation of germ cells and non-germinal cells (Sertoli cells & Leydig cells) work together in a synchronized fashion. Infertility is a genetic phenomenon and a variety of structural and numerical chromosome aberrations are well known to interfere with male infertility. The role of SycpT657C gene polymorphism has been poorly documented in the Indian population with special reference to non-obstructive azoospermic (NOA) cases. The present study has been designed with the aim to evaluate the following: 1) Cytogenetics study for evaluating the frequency of both structural and numerical chromosome variations in (NOA) cases by short-term peripheral blood lymphocyte (PBL) cultures;2) Genetic heterogenicity of the Sycp3 gene polymorphism by evaluating the frequency of T/C alleles. PCR-based analysis was carried out to characterize bands on agarose gel after ethidium bromide staining and bands were visualized on Gel-Doc system. Karyotype showing two new loci involving chromatid breaks 46,XY2q34, and 46,XY4q32 with the loss of DNA fragment of > 8.0 Mbp. Difference in the frequency of Robertsonian translocation (20%) and mosaicism (46,XY/47,XYY) were observed in the same karyotype. SYCP3 polymorphism shows significant changes in the frequency of TT genotype (43.33%) in homozygous conditions (wild type) and the calculated value of odd ratio (0.23) with a confidence interval varying from 0.08 - 0.71, suggesting an increased risk of developing infertility. To enhance the power of significance, two genotypes were combined together CC + TC which again showed significance with respect to controls. Data of the present study concludes that genetic heterogenicity of Sycp3 gene polymorphism and chromosomal aberrations with loss of DNA (8 Mbp) together confirm of developing risk of infertility in the NOA population.
文摘Objective:To determine the expression of the synaptonemal complex protein-3 (SYCP3) gene in men with nonobstructive azoospermia. Design:Cross-sectional case study. Setting:Avesina Infertility Clinic,Tehran,Iran. Patient(s):One hundred and ten consecutive infertile men presenting nonobstructive azoospermia. Intervention(s):Testicular biopsies for histopathological assessment and analyses of SYCP3 expression level by semiquantitative nested reverse transcription-polymerase chain reaction (RT-PCR). The SYCP3 levels were normalized to expression of the housekeeping phosphoglucomutase 1 gene. Main Outcome Measure(s):Expression of SYCP3 messenger ribonucleic acid (mRNA). Correlation of the histopathological findings with SYCP3 expression levels. Results(s):Testicular SYCP3 mRNA expression was observed in 67/110 (60.9%) patients. The expression level correlated with the degree of spermatogenic failure. Although it was expressed in patients with spermatogenesis and maturation arrest,a lack of expression was seen in all of those men with spermatogonial arrest,Sertoli cell-only syndrome,and testicular atrophy. Conclusion(s):These data indicate that SYCP3 is expressed in human testis and is restricted to germ cells. Our findings,in association with those obtained in experimental animals,shows that lack of SYCP3 expression in human testis may have a negative effect on spermatogenesis and male fertility.
基金supported by the Russian Foundation for Basic Research(Grant#16-04-00087)the Federal Agency for Scientific Organizations via the Institute of Cytology and Genetics(Grant#0324-2018-0019)
文摘Background: Meiotic recombination is an important source of genetic variability.Studies on mammals demonstrate a substantial interspecies variation in overall recombination rate, which is dependent mainly on chromosome(2 n) and chromosome arm number(FN).Bird karyotypes are very conservative with 2 n being about 78–82 and FN being 80–90 in most species.However, some families such as Apodidae(swifts) and Falconidae(falcons) show a substantial karyotypic variation.In this study, we describe the somatic and pachytene karyotypes of the male Common Swift(Apus apus) and the pachytene karyotype of the male Eurasian Hobby(Falco subbuteo) and estimate the overall number and distribution of recombination events along the chromosomes of these species.Methods: The somatic karyotype was examined in bone marrow cells.Pachytene chromosome spreads were prepared from spermatocytes of adult males.Synaptonemal complexes and mature recombination nodules were visualized with antibodies to SYCP3 and MLH1 proteins correspondingly.Results: The karyotype of the Common Swift consists of three metacentric, three submetacentric and two telocentric macrochromosomes and 31 telocentric microchromosomes(2 n = 78; FN = 90).It differs from the karyotypes of related Apodidae species described previously.The karyotype of the Eurasian Hobby contains one metacentric and 13 telocentric macrochromosomes and one metacentric and ten telocentric microchromosomes(2 n = 50; FN = 54) and is similar to that described previously in 2 n, but differs for macrochromosome morphology.Despite an about 40% difference in 2 n and FN, these species have almost the same number of recombination nodules per genome: 51.4 ± 4.3 in the swift and 51.1 ± 6.7 in the hobby.The distribution of the recombination nodules along the macrochromosomes was extremely polarized in the Common Swift and was rather even in the Eurasian Hobby.Conclusions: This study adds two more species to the short list of birds in which the number and distribution of recombination nodules have been examined.Our data confirm that recombination rate in birds is substantially higher than that in mammals, but shows rather a low interspecies variability.Even a substantial reduction in chromosome number does not lead to any substantial decrease in recombination rate.More data from different taxa are required to draw statistically supported conclusions about the evolution of recombination in birds.
