scholarly journals The molecular evolution of spermatogenesis across mammals

2021 ◽  
Author(s):  
Florent Murat ◽  
Noe Mbengue ◽  
Sofia Boeg Winge ◽  
Timo Trefzer ◽  
Evgeny Leushkin ◽  
...  
Keyword(s):  
Molecular Evolution ◽  
Sex Chromosome ◽  
Rapid Evolution ◽  
Cell Types ◽  
Reproductive Organ ◽  
Egg Laying ◽  
General Mechanism ◽  
Meiotic Sex Chromosome Inactivation ◽  
Selective Forces ◽  
Species Specific

The testis is a key male reproductive organ that produces gametes through the process of spermatogenesis. Testis morphologies and spermatogenesis evolve rapidly in mammals, presumably due to the evolutionary pressure on males to be reproductively successful. The rapid evolution of the testis was shown to be reflected at the molecular level based on bulk-tissue work, but the molecular evolution of individual spermatogenic cell types across mammalian lineages remains largely uncharacterized. Here we report evolutionary analyses of single-nucleus transcriptome data for testes from eleven species that cover the three major mammalian lineages (eutherians, marsupials, egg-laying monotremes) and birds (the evolutionary outgroup), and include seven key primates. Our analyses reveal that the rapid evolution of the testis is driven by accelerated fixation rates of gene expression changes, amino acid altering substitutions, and newly emerged genes in late spermatogenic stages - likely facilitated by reduced pleiotropic constraints, haploid selection, and a transcriptionally permissive chromatin environment. We identify temporal expression changes of individual genes across species, which may have contributed to the emergence of species-specific phenotypes, but also conserved expression programs underlying ancestral spermatogenic processes. Sex chromosome analyses show that genes predominantly expressed in spermatogonia (i.e., germ cells fueling spermatogenesis) and Sertoli cells (i.e., somatic supporting cells) independently accumulated on X chromosomes across mammals during evolution, presumably due to male-beneficial selective forces. Further work uncovered that the process of meiotic sex chromosome inactivation (MSCI) also occurs in monotremes and hence is common to the different mammalian sex chromosome systems, contrary to previous inferences. Thus, the general mechanism of meiotic silencing of unsynapsed chromatin (MSUC), which underlies MSCI, represents an ancestral mammalian feature. Together, our study illuminates the cellular and molecular evolution of mammalian spermatogenesis and associated selective forces, and provides a resource for investigating the biology of the testis across mammals.

Sortilin expression and uptake of α-galactosidase A: A general mechanism of endocytosis in Fabry disease cell types

2016 ◽  
Vol 117 (2) ◽  
pp. S106
Author(s):  
Jin-Song Shen ◽  
Taniqua S. Day ◽  
Xing-Li Meng ◽  
Zhi-Ping Liu ◽  
Raphael Schiffmann
Keyword(s):  
Fabry Disease ◽  
Cell Types ◽  
General Mechanism ◽  
Disease Cell

Sequence and spatial requirements for the tissue- and species-independent 3'-end processing mechanism of plant mRNA

1994 ◽  
Vol 14 (10) ◽  
pp. 6829-6838
Author(s):  
L Wu ◽  
T Ueda ◽  
J Messing
Keyword(s):  
Transcription Unit ◽  
Cauliflower Mosaic Virus ◽  
Upstream Region ◽  
General Mechanism ◽  
Upstream Sequence ◽  
Preference Order ◽  
Spatial Positioning ◽  
Species Specific ◽  
Zein Mrna ◽  
Processing Mechanism

Two cis-regulatory regions are required for efficient mRNA 3'-end processing of the maize 27-kDa zein mRNA: a region containing a duplicated AAUGAA poly(A) signal and a region that is present upstream from it. Strict spatial positioning of these two regions is required for efficient mRNA 3'-end processing. Insertion of a stuffer sequence as short as 17 or 18 bp either between the upstream region and the two AAUGAA motifs or between the two AAUGAA motifs drastically reduced the efficiency of 3'-end processing. Mutational analyses of the nucleotide preference at the fourth position of the AAUGAA motif revealed the preference order G > A >> C or U, suggesting that AAUAAA is neither a defective nor an optimal poly(A) signal for the 27-kDa zein mRNA. As for the 3' control region of the cauliflower mosaic virus (CaMV) transcription unit, the mRNA 3'-end processing mechanism mediated by the 27-kDa zein 3' control sequence is neither tissue nor species specific. The 3' upstream sequence of the 27-kDa zein gene can functionally replace that of the CaMV transcription unit. Conversely, the CaMV upstream sequence can mediate mRNA polyadenylation in the presence of a duplicated 27-kDa zein poly(A) signal. However, instead of the proximal poly(A) signal normally used in the 27-kDa zein mRNA, the distal signal is utilized. These results suggest that a general mechanism controls the 3'-end processing of plant mRNAs and that the cis-regulatory functions mediated by their upstream regions are interchangeable.

THE ROLE OF TRANSPOSABLE ELEMENTS IN ENDOCRINE CHANGES DURING AGING

2020 ◽  
pp. 418-428
Author(s):  
Р. Н. Мустафин ◽  
Э. К. Хуснутдинова
Keyword(s):  
Hormonal Regulation ◽  
Endocrine System ◽  
Cell Types ◽  
Key Factors ◽  
Dna Binding Domains ◽  
Binding Domains ◽  
Stage Of Development ◽  
Expression Of Genes ◽  
Transposon Activity ◽  
Species Specific

Одним из ключевых механизмов старения является изменение гормональной регуляции, для эффективного воздействия на которую с целью продления жизни необходимо определение первопричины данных процессов. В качестве молекулярных драйверов, управляющих динамикой уровня гормонов, могут служить транспозоны. Это связано с их использованием в качестве источников нуклеотидных последовательностей, воспринимающих специфические сигналы рибозимов, транскрипционных факторов, гормонов и их мессенджеров. В то же время, в эволюции транспозоны являются источниками рибозимов и белков, обладающих ДНК-связывающими доменами. Начиная с деления зиготы, видоспецифический состав и распределение транспозонов в геноме могут использоваться как биологическая кодировка, необходимая для последовательной и специфической для типов клеток экспрессии генов. Сделано предположение, что гормональная регуляция является одним из компонентов сложной системы управления онтогенезом под влиянием мобильных элементов. В качестве подтверждения приведены работы о роли транспозонов в управлении генами эндокринной системы, а также о влиянии гормонов на активность транспозонов. Исследование этих взаимосвязей может иметь перспективы для разработки методов продления жизни, так как эпигенетические изменения под влиянием транспозонов носят обратимый характер. Species-specific changes in the endocrine system are key factors in aging. Therefore, to prolong life, it is necessary to find regulators of the highest level, the changes of which lead to physiological aging. The molecular drivers that control dynamics of hormone levels can be transposons. This is due to the use of nucleotide sequences of transposons as binding sites that perceive specific signals of ribozymes, transcription factors, hormones and their messengers. At the same time, transposons are evolutionary sources of ribozymes and proteins that have DNA-binding domains. Starting from zygote division, the species-specific composition and distribution of transposons in the genome serves as a biological coding, which is necessary for the sequential expression of genes specific to cell types and stage of development. We suggest that hormonal regulation is one of the components of this complex system of regulation of ontogenesis under the control of transposons. To confirm our hypothesis, this review contains articles that prove the importance of transposons for species-specific control of endocrine system genes, as well as the effect of hormones on transposon activity. The research of these relationships is promising for the development of methods for the effective prolongation of life, since epigenetic changes under the influence of transposons are reversible.

Sexual Selection, Timing and an X–Y Homologous Gene: Did Homo Sapiens Speciate on the Y Chromosome?

2004 ◽  
Author(s):  
Tim J. Crow
Keyword(s):  
Sexual Selection ◽  
Sex Chromosome ◽  
Homo Sapiens ◽  
Single Gene ◽  
Critical Role ◽  
Hominid Evolution ◽  
Homologous Gene ◽  
Chromosomal Change ◽  
Species Specific ◽  
Sex Chromosome Aneuploidies

This chapter provides a theory of the speciation of modern Homo sapiens, that a single gene played a critical role in the transition from a precursor species. The theory is founded upon the following: firstly, the premise that hemispheric asymmetry is the defining feature of the human brain and the only plausible correlate of language; secondly, an argument for a specific candidate region (the Xq21.3/Yp11.2 region of homology) based upon the reciprocal deficits associated with the sex chromosome aneuploidies, and the course of chromosomal change in hominid evolution; and thirdly, a particular evolutionary mechanism (sexual selection acting on an X-Y-linked gene) to account for species-specific modification of what initially was a saltational change. These postulates relate to the case of modern Homo sapiens. On the basis of the recent literature, the discussion argues that the third premise has general significance as a mechanism of speciation.

scholarly journals Cause and Effectors: Whole-Genome Comparisons Reveal Shared but Rapidly Evolving Effector Sets among Host-Specific Plant-Castrating Fungi

mBio ◽  
2019 ◽  
Vol 10 (6) ◽  
Author(s):  
William C. Beckerson ◽  
Ricardo C. Rodríguez de la Vega ◽  
Fanny E. Hartmann ◽  
Marine Duhamel ◽  
Tatiana Giraud ◽  
...  
Keyword(s):  
Positive Selection ◽  
Plant Pathogens ◽  
Pfam Domain ◽  
Rapid Evolution ◽  
Host Specialization ◽  
Secreted Proteins ◽  
Smut Fungi ◽  
Core Proteins ◽  
Genes Encoding ◽  
Species Specific

ABSTRACT Plant pathogens utilize a portfolio of secreted effectors to successfully infect and manipulate their hosts. It is, however, still unclear whether changes in secretomes leading to host specialization involve mostly effector gene gains/losses or changes in their sequences. To test these hypotheses, we compared the secretomes of three host-specific castrating anther smut fungi (Microbotryum), two being sister species. To address within-species evolution, which might involve coevolution and local adaptation, we compared the secretomes of strains from differentiated populations. We experimentally validated a subset of signal peptides. Secretomes ranged from 321 to 445 predicted secreted proteins (SPs), including a few species-specific proteins (42 to 75), and limited copy number variation, i.e., little gene family expansion or reduction. Between 52% and 68% of the SPs did not match any Pfam domain, a percentage that reached 80% for the small secreted proteins, indicating rapid evolution. In comparison to background genes, we indeed found SPs to be more differentiated among species and strains, more often under positive selection, and highly expressed in planta; repeat-induced point mutations (RIPs) had no role in effector diversification, as SPs were not closer to transposable elements than background genes and were not more RIP affected. Our study thus identified both conserved core proteins, likely required for the pathogenic life cycle of all Microbotryum species, and proteins that were species specific or evolving under positive selection; these proteins may be involved in host specialization and/or coevolution. Most changes among closely related host-specific pathogens, however, involved rapid changes in sequences rather than gene gains/losses. IMPORTANCE Plant pathogens use molecular weapons to successfully infect their hosts, secreting a large portfolio of various proteins and enzymes. Different plant species are often parasitized by host-specific pathogens; however, it is still unclear whether the molecular basis of such host specialization involves species-specific weapons or different variants of the same weapons. We therefore compared the genes encoding secreted proteins in three plant-castrating pathogens parasitizing different host plants, producing their spores in plant anthers by replacing pollen. We validated our predictions for secretion signals for some genes and checked that our predicted secreted proteins were often highly expressed during plant infection. While we found few species-specific secreted proteins, numerous genes encoding secreted proteins showed signs of rapid evolution and of natural selection. Our study thus found that most changes among closely related host-specific pathogens involved rapid adaptive changes in shared molecular weapons rather than innovations for new weapons.

How the sperm triggers development of the egg: what have we learned and what can we expect in the next millennium?

Zygote ◽  
1999 ◽  
Vol 8 (S1) ◽  
pp. S7-S8
Author(s):  
David Epel
Keyword(s):  
Sea Urchin ◽  
Cell Biology ◽  
Control Cell ◽  
Rapid Evolution ◽  
Cell Activity ◽  
Turn Of The Century ◽  
Direct Demonstration ◽  
Creative Research ◽  
Contemporary Work ◽  
Species Specific

The problem of how the sperm activates the egg has captivated the attention of cell and developmental biologists since the turn of the century. An early focus concerned species-specific fertilisation and the pioneering work of Lilly and Tyler (Tyler & Tyler, 1966) used immunological analogies to provide explanations of species-specific fertilisation. Contemporary work has focused on the identity of unique receptors on the sperm and the egg as exemplified in the work of Lennarz (Ohlendieck & Lennarz, 1996), Vacquier (Vacquier, et al., 1995) and Wasserman (1999). Lately, this approach has provided unexpected insights on how speciation might occur. Speciation requires reproductive isolation and creative research from the Vacquier laboratory has demonstrated how reproductive barriers might occur through rapid evolution of sperm/egg recognition systems (Lee et al., 1995).Studies on the cell biology of activation received a major impetus in the 1930s with Mazia's observation of a calcium increase in eggs of the sea urchin following fertilisation (Mazia, 1937). His discovery, however, was a premature one in that there was no satisfactory model at that time for explaining how a calcium increase could affect cell activity. It took almost 40 years to develop a paradigm, and this came from studies on muscle and nerve which revealed how calcium increases could somehow control cell activity. Work in the 1970s rapidly established a similar role for calcium in activation of the egg at fertilisation. The first break-through was the direct demonstration by Steinhardt & Epel (1974) that calcium was involved in egg activation, through manipulation of calcium levels in sea urchin oocytes by use of calcium ionophores.

scholarly journals Zfygenes are required for efficient meiotic sex chromosome inactivation (MSCI) in spermatocytes

2016 ◽  
pp. ddw344
Author(s):  
Nadège Vernet ◽  
Shantha K. Mahadevaiah ◽  
Dirk G. de Rooij ◽  
Paul S. Burgoyne ◽  
Peter J. I. Ellis
Keyword(s):  
Sex Chromosome ◽  
Chromosome Inactivation ◽  
Meiotic Sex Chromosome Inactivation ◽  
Sex Chromosome Inactivation
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