The Male Hypermethylation (MHM) Region on the Chicken Z Chromosome: Female-Specific Transcription and its Biological Implication

Hint is a universally conserved, dimeric AMP-lysine hydrolase encoded on the avian Z chromosome. Tandemly repeated on the female-specific W chromosome, Asw encodes a potentially sex-determining, dominant-negative Hint dimerization partner whose substrate-interacting residues were specifically altered in evolution. To test the hypothesis that Gln127 of Asw is responsible for depression and/or alteration of Hint enzyme activity, a corresponding mutant was created in the chicken Hint homodimer, and a novel substrate was developed that links reversal of AMP-lysine modification to aminomethylcoumarin release. Strikingly, the Hint-W123Q substitution reduced kcat/ Km for AMP-lysine hydrolysis 17-fold, while it increased specificity for AMP- para-nitroaniline hydrolysis by 160-fold. The resulting 2,700-fold switch in enzyme specificity suggests that Gln127 could be the dominant component of Asw dominant negativity in avian feminization.

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A conserved role of the duplicated Masculinizer gene in sex determination of the Mediterranean flour moth, Ephestia kuehniella

10.1101/2021.02.15.431251 ◽

2021 ◽

Author(s):

Sander Visser ◽

Anna Voleníková ◽

Petr Nguyen ◽

Eveline C. Verhulst ◽

František Marec

Keyword(s):

Sex Determination ◽

Early Embryogenesis ◽

Ephestia Kuehniella ◽

Z Chromosome ◽

Female Development ◽

Biased Sex Ratio ◽

The Mediterranean ◽

Female Specific ◽

Mediterranean Flour Moth

AbstractSex determination in the silkworm, Bombyx mori, is based on Feminizer (Fem), a W-linked Fem piRNA that triggers female development in WZ individuals, and the Z-linked Masculinizer (Masc), which initiates male development and dosage compensation in ZZ individuals. While Fem piRNA is missing in a close relative of B. mori, Masc determines sex in several representatives of distant lepidopteran lineages. We studied the molecular mechanisms of sex determination in the Mediterranean flour moth, Ephestia kuehniella (Pyralidae). We identified an E. kuehniella Masc ortholog, EkMasc, and its paralog resulting from a recent duplication, EkMascB. Both genes are located on the Z chromosome and encode a similar Masc protein that contains two conserved domains but has lost the conserved double zinc finger domain. We developed PCR-based genetic sexing and demonstrated a peak in the expression of EkMasc and EkMascB genes only in early male embryos. Simultaneous knock-down experiments of both EkMasc and EkMascB using RNAi during early embryogenesis led to a shift from male- to female-specific splicing of the E. kuehniella doublesex gene (Ekdsx), their downstream effector, in ZZ embryos and resulted in a strong female-biased sex-ratio. Our results thus confirmed the conserved role of both EkMasc and EkMascB genes in masculinization. We suggest that the C-terminal proline-rich domain, we have identified in all functionally confirmed Masc proteins, in conjunction with the masculinizing domain, is important for transcriptional regulation of sex determination in Lepidoptera. The function of the Masc double zinc finger domain is still unknown, but appears to have been lost in E. kuehniella.Author summaryThe sex-determining cascade in the silkworm, Bombyx mori, differs greatly from those of other insects. In B. mori, female development is initiated by Fem piRNA expressed from the W chromosome during early embryogenesis. Fem piRNA silences Masculinizer (Masc) thereby blocking the male pathway resulting in female development. It is currently unknown whether this cascade is conserved across Lepidoptera. In the Mediterranean flour moth, Ephestia kuehniella, we identified an ortholog of Masc and discovered its functional duplication on the Z chromosome, which has not yet been found in any other lepidopteran species. We provide two lines of evidence that both the EkMasc and EkMascB genes play an essential role in masculinization: (i) they show a peak of expression during early embryogenesis in ZZ but not in WZ embryos and (ii) their silencing by RNAi results in female-specific splicing of the E. kuehniella doublesex gene (Ekdsx) in ZZ embryos and in a female-biased sex ratio. Our results suggest a conserved role of the duplicated Masc gene in sex determination of E. kuehniella.

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Identification and Characterization of the Masculinizing Function of the Helicoverpa armigera Masc Gene

International Journal of Molecular Sciences ◽

10.3390/ijms22168650 ◽

2021 ◽

Vol 22 (16) ◽

pp. 8650

Author(s):

Zhongyuan Deng ◽

Yakun Zhang ◽

Yalu Li ◽

Kaiyuan Huang ◽

Xuewei Chen ◽

...

Keyword(s):

Sex Determination ◽

Helicoverpa Armigera ◽

Embryonic Cell ◽

Z Chromosome ◽

Downstream Target ◽

Sex Development ◽

Downstream Target Gene ◽

Helicoverpa Armígera ◽

Splicing Isoforms ◽

Female Specific

The Masculinizer (Masc) gene has been known to control sex development and dosage compensation in lepidopterans. However, it remains unclear whether its ortholog exists and plays the same roles in distantly related lepidopterans such as Helicoverpa armigera. To address this question, we cloned Masc from H. armigera (HaMasc), which contains all essential functional domains of BmMasc, albeit with less than 30% amino acid sequence identity with BmMasc. Genomic PCR and qPCR analyses showed that HaMasc is a Z chromosome-linked gene since its genomic content in males (ZZ) was two times greater than that in females (ZW). RT-PCR and RT-qPCR analyses revealed that HaMasc expression was sex- and stage-biased, with significantly more transcripts in males and eggs than in females and other stages. Transfection of a mixture of three siRNAs of HaMasc into a male embryonic cell line of H. armigera led to the appearance of female-specific mRNA splicing isoforms of H. armigera doublesex (Hadsx), a downstream target gene of HaMasc in the H. armigera sex determination pathway. The knockdown of HaMasc, starting from the third instar larvae resulted in a shift of Hadsx splicing from male to female isoforms, smaller male pupa and testes, fewer but larger/longer spermatocytes and sperm bundles, delayed pupation and internal fusion of the testes and follicles. These data demonstrate that HaMasc functions as a masculinizing gene in the H. armigera sex-determination cascade.

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Female-specific hyperacetylation of histone H4 in the chicken Z chromosome

Chromosome Research ◽

10.1007/s10577-005-1505-4 ◽

2005 ◽

Vol 13 (2) ◽

pp. 205-214 ◽

Cited By ~ 43

Author(s):

Laura Bisoni ◽

Laura Batlle-Morera ◽

Adrian P. Bird ◽

Miho Suzuki ◽

Heather A. McQueen

Keyword(s):

Z Chromosome ◽

Histone H4 ◽

Female Specific

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Molecular Evolution of the Avian CHD1 Genes on the Z and W Sex Chromosomes

Genetics ◽

10.1093/genetics/155.4.1903 ◽

2000 ◽

Vol 155 (4) ◽

pp. 1903-1912 ◽

Cited By ~ 2

Author(s):

Anna-Karin Fridolfsson ◽

Hans Ellegren

Keyword(s):

Molecular Evolution ◽

Sex Chromosomes ◽

Sequence Data ◽

Neutral Evolution ◽

Z Chromosome ◽

W Chromosome ◽

Effective Population ◽

Synonymous Substitutions ◽

Nonsynonymous Substitutions ◽

Female Specific

Abstract Genes shared between the nonrecombining parts of the two types of sex chromosomes offer a potential means to study the molecular evolution of the same gene exposed to different genomic environments. We have analyzed the molecular evolution of the coding sequence of the first pair of genes found to be shared by the avian Z (present in both sexes) and W (female-specific) sex chromosomes, CHD1Z and CHD1W. We show here that these two genes evolve independently but are highly conserved at nucleotide as well as amino acid levels, thus not indicating a female-specific role of the CHD1W gene. From comparisons of sequence data from three avian lineages, the frequency of nonsynonymous substitutions (Ka) was found to be higher for CHD1W (1.55 per 100 sites) than for CHD1Z (0.81), while the opposite was found for synonymous substitutions (Ks, 13.5 vs. 22.7). We argue that the lower effective population size and the absence of recombination on the W chromosome will generally imply that nonsynonymous substitutions accumulate faster on this chromosome than on the Z chromosome. The same should be true for the Y chromosome relative to the X chromosome in XY systems. Our data are compatible with a male-biased mutation rate, manifested by the faster rate of neutral evolution (synonymous substitutions) on the Z chromosome than on the female-specific W chromosome.

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Absence of W Chromosome in Psychidae Moths and Implications for the Theory of Sex Chromosome Evolution in Lepidoptera

Genes ◽

10.3390/genes10121016 ◽

2019 ◽

Vol 10 (12) ◽

pp. 1016

Author(s):

Martina Hejníčková ◽

Petr Koutecký ◽

Pavel Potocký ◽

Irena Provazníková ◽

Anna Voleníková ◽

...

Keyword(s):

Genome Size ◽

Sex Chromosome ◽

Phylogenetic Position ◽

Z Chromosome ◽

Comparative Genomic ◽

W Chromosome ◽

Sex Chromatin ◽

Sex Chromosome System ◽

The Common ◽

Female Specific

Moths and butterflies (Lepidoptera) are the largest group with heterogametic females. Although the ancestral sex chromosome system is probably Z0/ZZ, most lepidopteran species have the W chromosome. When and how the W chromosome arose remains elusive. Existing hypotheses place the W origin either at the common ancestor of Ditrysia and Tischeriidae, or prefer independent origins of W chromosomes in these two groups. Due to their phylogenetic position at the base of Ditrysia, bagworms (Psychidae) play an important role in investigating the W chromosome origin. Therefore, we examined the W chromosome status in three Psychidae species, namely Proutia betulina, Taleporia tubulosa, and Diplodoma laichartingella, using both classical and molecular cytogenetic methods such as sex chromatin assay, comparative genomic hybridization (CGH), and male vs. female genome size comparison by flow cytometry. In females of all three species, no sex chromatin was found, no female-specific chromosome regions were revealed by CGH, and a Z-chromosome univalent was observed in pachytene oocytes. In addition, the genome size of females was significantly smaller than males. Overall, our study provides strong evidence for the absence of the W chromosome in Psychidae, thus supporting the hypothesis of two independent W chromosome origins in Tischeriidae and in advanced Ditrysia.

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A ZZ/ZW Sex Chromosome System in Cephalochordate Amphioxus

Genetics ◽

10.1534/genetics.120.303051 ◽

2020 ◽

Vol 214 (3) ◽

pp. 617-622

Author(s):

Chenggang Shi ◽

Xiaotong Wu ◽

Liuru Su ◽

Chaoqi Shang ◽

Xuewen Li ◽

...

Keyword(s):

Sex Determination ◽

Mutant Strain ◽

Sex Chromosome ◽

Female Offspring ◽

Phylogenetic Position ◽

Z Chromosome ◽

Transcription Activator ◽

Sex Chromosome System ◽

Female Specific ◽

Determination Mechanism

Sex determination is remarkably variable among animals with examples of environmental sex determination, male heterogametic (XX/XY) and female heterogametic (ZZ/ZW) chromosomal sex determination, and other genetic mechanisms. The cephalochordate amphioxus occupies a key phylogenetic position as a basal chordate and outgroup to vertebrates, but its sex determination mechanism is unknown. During the course of generating Nodal mutants with transcription activator-like effector nucleases (TALENs) in amphioxus Branchiostoma floridae, serendipitously, we generated three mutant strains that reveal the sex determination mechanism of this animal. In one mutant strain, all heterozygous mutant offspring over three generations were female and all wild-type descendants were male. This pattern suggests the Nodal allele targeted is on a female-specific W chromosome. A second mutant showed the same W-linked inheritance pattern, with a female heterozygote passing the mutation only to daughters. In a third mutant strain, both male and female offspring could be heterozygous, but a female heterozygote passed the mutation only to sons. This pattern is consistent with the targeted allele being on a Z chromosome. We found an indel polymorphism linked to a Nodal allele present in most females, but no males in our cultured population. Together, these results indicate that Nodal is sex chromosome-linked in B. floridae, and that B. floridae has a ZZ/ZW sex chromosome system.

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