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Teranishi, Mika; Shimada, Yukiko; Hori, Tomohide; Nakabayashi, Osamu; Kikuchi, Tateki; Macleod, Tracy; Pym, R. A.; Sheldon, B. L.; Solovei, Irina; Macgregor, H. C.; Mizuno, Shigeki

doi:10.1023/a:1009235120741

Cited by 133 publications

(50 citation statements)

References 30 publications

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“…Notably, a very small number Z linked sequences were female-biased, in both tissues (Figure 1B). These derived from the MHM locus (Male Hypermethylated), a curious sequence that has previously been reported to be female specific and hypothesised to play a role in localised dosage compensation (upregulation of some neighbouring Z genes in females) [33,34]. …”

Section: Resultsmentioning

confidence: 99%

RNA sequencing reveals sexually dimorphic gene expression before gonadal differentiation in chicken and allows comprehensive annotation of the W-chromosome

et al. 2013

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BackgroundBirds have a ZZ male: ZW female sex chromosome system and while the Z-linked DMRT1 gene is necessary for testis development, the exact mechanism of sex determination in birds remains unsolved. This is partly due to the poor annotation of the W chromosome, which is speculated to carry a female determinant. Few genes have been mapped to the W and little is known of their expression.ResultsWe used RNA-seq to produce a comprehensive profile of gene expression in chicken blastoderms and embryonic gonads prior to sexual differentiation. We found robust sexually dimorphic gene expression in both tissues pre-dating gonadogenesis, including sex-linked and autosomal genes. This supports the hypothesis that sexual differentiation at the molecular level is at least partly cell autonomous in birds. Different sets of genes were sexually dimorphic in the two tissues, indicating that molecular sexual differentiation is tissue specific. Further analyses allowed the assembly of full-length transcripts for 26 W chromosome genes, providing a view of the W transcriptome in embryonic tissues. This is the first extensive analysis of W-linked genes and their expression profiles in early avian embryos.ConclusionSexual differentiation at the molecular level is established in chicken early in embryogenesis, before gonadal sex differentiation. We find that the W chromosome is more transcriptionally active than previously thought, expand the number of known genes to 26 and present complete coding sequences for these W genes. This includes two novel W-linked sequences and three small RNAs reassigned to the W from the Un_Random chromosome.

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Section: Resultsmentioning

confidence: 99%

RNA sequencing reveals sexually dimorphic gene expression before gonadal differentiation in chicken and allows comprehensive annotation of the W-chromosome

et al. 2013

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“…Some Z genes appear to be equivalently expressed in the two sexes, suggesting some compensation mechanism, but in other cases both Z alleles are expressed (23,24,55,56). Three Z genes in zebra finches (trkB, CHD1Z, and PKCIZ) all show generally higher expression in male brain (20,22), raising the possibility that Z genes are typically expressed at a higher level in males.…”

Section: Discussionmentioning

confidence: 99%

Sexually dimorphic expression of trkB, a Z-linked gene, in early posthatch zebra finch brain

Chen

Agate²,

Itoh³

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

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Sexual differentiation of the zebra finch (Taeniopygia guttata) neural song circuit is thought to be initiated by sex differences in sex chromosome gene expression in brain cells. One theory is that Z-linked genes, present in the male's ZZ genome at double the dose of females' (ZW), are expressed at higher levels and trigger masculine patterns of development. We report here that trkB (tyrosine kinase receptor B) is Z-linked in zebra finches. trkB is the receptor for neurotrophic factors BDNF and neurotrophin 4, and mediates their influence on neuronal survival, migration, and specification. trkB mRNA is expressed at a higher level in the male telencephalon or whole brain than in corresponding regions of the female in adulthood, and at posthatch day (P) 6, when the song circuit is undergoing sexual differentiation. Moreover, this expression is higher in the song nucleus high vocal center (HVC) than in the surrounding telencephalon at P6, and in males relative to females. In addition, trkB protein is expressed more highly in male than female whole brain at P6. These results establish trkB as a candidate factor that contributes to masculine differentiation of HVC because of its Z-linkage, which leads to sex differences in expression. BDNF is known to be stimulated by estrogen and to be expressed at higher levels in males than females at later ages in HVC. Thus, the trkB-BDNF system may be a focal point for convergent masculinizing influences of Z-linked factors and hormones.sex determination ͉ song ͉ Z chromosome

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“…In male MHM locus is hypermethylated and inactivated in the sense RNA synthesis, and therefore both alleles DMRT1 are not transcribed. MHM locus consists of approximately 200 repeats of a sequence 2.2 kb and transcribed into noncoding heterogeneous RNA, which accumulates in the nucleus of female locally to the site of transcription [31]. It was demonstrated specific chromatin modification for females near MHM l. Chromatin chickens Zp21 site, including the locus MHM, enriched histone acetylation of H4 lysine 16 in females but not in males [32].…”

Section: Sexual Differentiation In Birdsmentioning

confidence: 99%

Problems of Birds Sex Determination

Trukhina¹,

Smirnov²

2014

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Sex determination system in birds is characterized by a homo-(Neognatae) and heteromorphic (Paleognatae) sex chromosomes. Heterogametic sex is female (ZZ/ZW system). DMRT1 gene is a gene regarded as a main male sex determining factor in this group of animals. The question remains about the participation of other factors (HEMOGEN, AMH etc.) in appearance of testis, and the role of steroid hormones in formation of ovaries. Complete sex inversion is not typical for species with genotypic sex determination (GSD), although the effect of estrogen metabolites is noted for birds. For birds epigenetic mechanisms of regulation (methylation of DNA and non-coding RNA) have been described for sex controlling genes such as CYP19A1 and DMRT1.

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Cited by 133 publications

References 30 publications

RNA sequencing reveals sexually dimorphic gene expression before gonadal differentiation in chicken and allows comprehensive annotation of the W-chromosome

RNA sequencing reveals sexually dimorphic gene expression before gonadal differentiation in chicken and allows comprehensive annotation of the W-chromosome

Sexually dimorphic expression of trkB, a Z-linked gene, in early posthatch zebra finch brain

Problems of Birds Sex Determination

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