Successful transmission and transcriptional deployment of a human chromosome via mouse male meiosis
- University of Cambridge, United Kingdom
- University of Oxford, United Kingdom
- Science for Life Laboratory, Sweden
Abstract
Most human aneuploidies originate maternally, due in part to the presence of highly stringent checkpoints during male meiosis. Indeed, male sterility is common among aneuploid mice used to study chromosomal abnormalities, and male germline transmission of exogenous DNA has been rarely reported. Here we show that despite aberrant testis architecture, males of the aneuploid Tc1 mouse strain produce viable sperm and transmit human chromosome 21 to create aneuploid offspring. In these offspring, we mapped transcription, transcriptional initiation, enhancer activity, non-methylated DNA and transcription factor binding in adult tissues. Remarkably, when compared with mice derived from female passage of human chromosome 21, the chromatin condensation during spermatogenesis and the extensive epigenetic reprogramming specific to male germline transmission resulted in almost indistinguishable patterns of transcriptional deployment. Our results reveal an unexpected tolerance of aneuploidy during mammalian spermatogenesis, and the surprisingly robust ability of mouse developmental machinery to accurately deploy an exogenous chromosome, regardless of germline transmission.
Data availability
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Chip-Seq analysis of human chromosome 21 after its passage through either the female or male mouse germlinePublicly available at the EBI European Nucleotide Archive (accession no: E-MTAB-4913).
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BioCAP-Seq analysis of human chromosome 21 after its passage through either the mouse male germlinePublicly available at the EBI European Nucleotide Archive (accession no: E-MTAB-4930).
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RNA-Seq in liver of Tc1 mice carrying human chromosome 21 passaged through either the female or male germlinePublicly available at the EBI European Nucleotide Archive (accession no: E-MTAB-4912).
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E-MTAB-1104 - ChIP-seq of human and transgenic mouse adult liver, testes & kidney tissue to investigate epigenetic comparisonPublicly available at the EBI European Nucleotide Archive (accession no: E-MTAB-1104).
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E-MTAB-2633 - ChIP-Seq analysis of regulatory evolution in 20 mammalsPublicly available at the EBI European Nucleotide Archive (accession no: E-MTAB-2633).
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E-TABM-722 - ChIP-seq of Canis familiaris, Gallus gallus, Mus musculus, Homo sapiens, Monodelphis domestica to investigate CEBPA and HNF4a binding in five vertebratesPublicly available at the EBI European Nucleotide Archive (accession no: E-TABM-722).
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An evolutionarily conserved DNA-encoded logic shapes CpG island formationPublicly available at the NCBI Gene Expression Omnibus (accession no: GSE72208).
Article and author information
Author details
Funding
Cancer Research UK (A20412)
- Christina Ernst
- Sarah J Aitken
- Nils Eling
- Frances Connor
- Tim F Rayner
- Margus Lukk
- Claudia Kutter
- Duncan T Odom
European Research Council (615584)
- Duncan T Odom
Wellcome (098024/Z/11/Z)
- Robert J Klose
Wellcome (106563/Z/14/A)
- Sarah J Aitken
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Ethics
Animal experimentation: This investigation was approved by the Animal Welfare and Ethics Review Board and followed the Cambridge Institute guidelines for the use of animals in experimental studies under Home Office license PPL 70/7535.
Human subjects: Previously published human data from Ward et al. 2013 were used for comparisons in this study.
Copyright
© 2016, Ernst et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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Successful transmission and transcriptional deployment of a human chromosome via mouse male meiosis
eLife 5:e20235.
https://doi.org/10.7554/eLife.20235
Further reading
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- Chromosomes and Gene Expression
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Among the major classes of RNAs in the cell, tRNAs remain the most difficult to characterize via deep sequencing approaches, as tRNA structure and nucleotide modifications can each interfere with cDNA synthesis by commonly-used reverse transcriptases (RTs). Here, we benchmark a recently-developed RNA cloning protocol, termed Ordered Two-Template Relay (OTTR), to characterize intact tRNAs and tRNA fragments in budding yeast and in mouse tissues. We show that OTTR successfully captures both full-length tRNAs and tRNA fragments in budding yeast and in mouse reproductive tissues without any prior enzymatic treatment, and that tRNA cloning efficiency can be further enhanced via AlkB-mediated demethylation of modified nucleotides. As with other recent tRNA cloning protocols, we find that a subset of nucleotide modifications leave misincorporation signatures in OTTR datasets, enabling their detection without any additional protocol steps. Focusing on tRNA cleavage products, we compare OTTR with several standard small RNA-Seq protocols, finding that OTTR provides the most accurate picture of tRNA fragment levels by comparison to "ground truth" Northern blots. Applying this protocol to mature mouse spermatozoa, our data dramatically alter our understanding of the small RNA cargo of mature mammalian sperm, revealing a far more complex population of tRNA fragments - including both 5′ and 3′ tRNA halves derived from the majority of tRNAs – than previously appreciated. Taken together, our data confirm the superior performance of OTTR to commercial protocols in analysis of tRNA fragments, and force a reappraisal of potential epigenetic functions of the sperm small RNA payload.
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