Structural characteristics of genome organization in amphibians: Differential staining of chromosomes and DNA structure

Birstein, Vadim J.

doi:10.1007/bf01810826

Cited by 17 publications

(7 citation statements)

References 226 publications

(220 reference statements)

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“…Structural studies using restriction-enzyme banding in Odontophrynus Beçak and Kobashi, 2004 for review) suggested that the difficulty in obtaining G-bands in anurans would be caused by the lower number of CG sequences (probably arranged in small agglomerations) or due to higher chromatin packing, as previously proposed (Schmid, 1978;Birstein, 1982;Bernardi et al, 1985;Schmid and de Almeida, 1988).…”

Section: Methylation Signalsmentioning

confidence: 86%

Review Polyploidy and epigenetic events in the evolution of Anura

Ml¹

2014

Genet. Mol. Res.

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ABSTRACT. This article reviews the polyploidy events that have long been demonstrated to play a role in the evolution of Anura, while also discussing the importance of epigenetic control of gene expression and diversity. Findings on Brazilian autopolyploid anurans, mainly of the genus Odontophrynus, obtained in previous studies on their cytogenetics, chromatin ultrastructure, and molecular gene regulation are discussed here. Our data on genome duplication and on epigenetic events were analyzed here regarding phylogenetic trees, including the classic 2R model for vertebrate evolution and the growing evidence of similar epigenetic mechanisms in animal and allopolyploid plants. We propose that polyploidy and epigenetic events led to rapid Anura diversity and speciation. Also, recent advances in molecular studies in other organisms led us to revisit some controversial models of evolution.

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Section: Methylation Signalsmentioning

confidence: 86%

Review Polyploidy and epigenetic events in the evolution of Anura

Ml¹

2014

Genet. Mol. Res.

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“…Extensive studies have dealt with the pattern of heterochromatin distribution on the chromosomes of different Triturus species (for reviews ScHMID 1980;BIRSTEIN 1982), revealing species-specific differences superimposed on a common pattern. The general pattern of heterochromatin distribution involves centromeric and pericentromeric regions.…”

Section: Introductionmentioning

confidence: 99%

Heterochromatin heterogeneity inTriturus marmoratus(Urodela: Salamandridae) demonstrated with specific DNA-binding fluorochromes and «in situ» restriction endonuclease/nick translation

et al. 1993

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SUMMARY -The chromosomes of Triturus marmoratus have been studied using base-specific fluorochromes, and restriction enzyme digestion followed by nick translation to reveal the sites of specific DNA sequences. Much of the heterochromatin of this newt contains sufficient concentrations of AT-and GC-rich DNAs to be detected by specific fluorochromes. Our application of the restriction enzyme/nick translation to newt chromosomes for the first time shows that this procedure is particularly valuable for studying the organisation of heterochromatin in these organisms. The centromeres of all chromosomes except those of pairs 10, 11 and 12 had similar properties; a positive reaction with DA/DAPI, chromomycin/DA, Hae III/nick translation and Hinf 1/nick translation, but a negative reaction with Eco Rl/nick translation. The reactions of the centromeres with the restriction enzyme/nick translation procedures can be correlated with the known properties of the satellite DNAs contained in these regions. On the other hand, the large heteromorphic blocks of heterochromatin on the long arms of chromosome I, were shown to be highly heterogenous when digested with Hae III or Eco RI and nick translated.

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“…Although sperm nuclear condensation appears to be an essentially conserved process, the protein complements present in the sperm chromatin vary considerably between species and thus, the specific patterns and mechanisms by which the chromatin is packaged are also likely to be highly divergent (Manochantr et al 2005;Enciso et al 2011). There is, however, unanimous agreement that the preliminary chromatin organisation of early-stage spermatids resembles the nucleosomal structure of mitotic somatic cells (Birstein 1982). Although it is widely accepted that the sperm chromatin structure of eutherian mammals is basically similar across species (Birstein 1982), little comparative information exists, especially with respect to amphibians.…”

Section: Dna Packaging In Mammalian and Lower Vertebrate Sperm Nucleimentioning

confidence: 91%

“…The first level of chromatin packing in amphibians does not differ from that in mammals (Birstein 1982). During the initial stages of spermatogenesis, sperm DNA is closely associated with histones and is organised into nucleosomal core particles similar to somatic cells (D'Occhio et al 2007).…”

Section: Chromatin Remodelling In Mammalian Spermatozoamentioning

confidence: 94%

“…There is, however, unanimous agreement that the preliminary chromatin organisation of early-stage spermatids resembles the nucleosomal structure of mitotic somatic cells (Birstein 1982). Although it is widely accepted that the sperm chromatin structure of eutherian mammals is basically similar across species (Birstein 1982), little comparative information exists, especially with respect to amphibians. Therefore, this review will primarily focus on DNA packaging in mammalian sperm but with reference to amphibians where this information is available.…”

Section: Dna Packaging In Mammalian and Lower Vertebrate Sperm Nucleimentioning

confidence: 99%

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Amphibian sperm DNA fragmentation

Pollock¹

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There are extremely limited studies that have investigated DNA fragmentation in amphibians and even less information exists pertaining to DNA fragmentation in the spermatozoa.A DNA fragmentation assay applied and validated for amphibian spermatozoa would not only provide the first evidence of this phenomenon in a new major taxon, but also prove a valuable tool for developing improvements in ART used in the captive propagation of threatened and endangered species. Consequently, the fundamental aim of this project was the development and validation of the sperm chromatin dispersion (SCD) test for amphibian spermatozoa with the purpose of investigating the dynamic behaviour of amphibian sperm DNA in response to cryopreservation.The SCD test was first applied to African clawed frog (Xenopus laevis) as an amphibian sperm model using a species-specific modified lysing solution for protein depletion. Sperm DNA fragmentation (SDF) was assessed immediately following activation of sperm motility (T0) and again after one hour and 24 hours of incubation in order to produce a range of spermatozoa with differing levels of DNA damage. The SCD procedure resulted in the production of three nuclear morphotypes; amphibian sperm morphotype 1 (ASM-1) and ASM-2 showed no evidence of DNA damage, whereas ASM-3 spermatozoa were highly fragmented with large halos of dispersed DNA fragments and a reduced nuclear core. Levels of SDF revealed by the SCD test were highly correlated with results produced using in situ nick hybridisation with DNA-specific molecular probes (ISNT) and the double comet assay (r = 0.9613). The alkaline step of the double-comet assay revealed the extensive presence of structural single-stranded DNA breaks (SSB) and provided grounds for the suggestion that alkali labile sites (ALS) are a constitutive feature of African clawed frog sperm chromatin.SDF is a dynamic process and has been shown to increase with incubation at room temperature as well as following cryopreservation. However, the mechanisms of DNA cryoinjury and the resulting effect on the potential reproductive output of ART remain open to interpretation.Consequently, dynamic changes to the basal level of DNA fragmentation were examined in fresh African clawed frog spermatozoa in comparison with the post-thaw integrity of cryopreserved (-80 °C) and frozen (-20 °C) sperm DNA. SDF was examined initially at T0 and over incubation of up to 60 minutes. The difference in SDF was only marginal for fresh, frozen (-20 °C) and cryopreserved (-80 °C) spermatozoa examined at the onset of the experiment immediately upon thawing, however, a significant increase (p = 0.004) in SDF, albeit of a low magnitude, was observed in activated ii cryopreserved (-80 °C) spermatozoa following incubation. Although African clawed frog spermatozoa appeared to be highly resistant to cryopreservation-induced DNA damage, cryopreserved-thawed spermatozoa yielded a significantly lower (p = 0.0065) fertilisation rate than fresh spermatozoa.In order to provide further insight into cryo...

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Structural characteristics of genome organization in amphibians: Differential staining of chromosomes and DNA structure

Cited by 17 publications

References 226 publications

Review Polyploidy and epigenetic events in the evolution of Anura

Review Polyploidy and epigenetic events in the evolution of Anura

Heterochromatin heterogeneity inTriturus marmoratus(Urodela: Salamandridae) demonstrated with specific DNA-binding fluorochromes and «in situ» restriction endonuclease/nick translation

Amphibian sperm DNA fragmentation

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