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Sexually dimorphic and sex-independent left-right asymmetries in chicken embryonic gonads.

Intarapat S, Stern CD - PLoS ONE (2013)

Bottom Line: Expression is asymmetric in both sexes: at stage 35 the left gonad contains significantly more germ cells than the right.Other pluripotency-associated markers (PouV/Oct3/4, Nanog and Sox2) also show asymmetric expression (more expressing cells on the left) in both sexes, but this asymmetry is at least partly due to expression in stromal cells of the developing gonad, and the pattern is different for all the genes.Therefore germ cell and pluripotency-associated genes show both sex-dependent and independent left-right asymmetry and a complex pattern of expression.

View Article: PubMed Central - PubMed

Affiliation: Department of Anatomy, Faculty of Science, Mahidol University, Bangkok, Thailand.

ABSTRACT
Female birds develop asymmetric gonads: a functional ovary develops on the left, whereas the right gonad regresses. In males, however, testes develop on both sides. We examined the distribution of germ cells using Vasa/Cvh as a marker. Expression is asymmetric in both sexes: at stage 35 the left gonad contains significantly more germ cells than the right. A similar expression pattern is seen for expression of ERNI (Ens1), a gene expressed in chick embryonic stem cells while they self-renew, but downregulated upon differentiation. Other pluripotency-associated markers (PouV/Oct3/4, Nanog and Sox2) also show asymmetric expression (more expressing cells on the left) in both sexes, but this asymmetry is at least partly due to expression in stromal cells of the developing gonad, and the pattern is different for all the genes. Therefore germ cell and pluripotency-associated genes show both sex-dependent and independent left-right asymmetry and a complex pattern of expression.

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Left-right asymmetric gene expression in male embryonic gonads: Cvh (A), cPouV (B), cNanog (C), cSox2 (D) and ERNI (E) positive cells are expressed in both left and right ovaries.Ovarian sections exhibit germ cells, Cvh (A’) and cPouV (B’), cNanog (C’), cSox2 (D’) and ERNI (E’) positive cells. Abbreviations: RO = Right ovary, LO = Left ovary. (Scale bar = 50 µm).
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pone-0069893-g002: Left-right asymmetric gene expression in male embryonic gonads: Cvh (A), cPouV (B), cNanog (C), cSox2 (D) and ERNI (E) positive cells are expressed in both left and right ovaries.Ovarian sections exhibit germ cells, Cvh (A’) and cPouV (B’), cNanog (C’), cSox2 (D’) and ERNI (E’) positive cells. Abbreviations: RO = Right ovary, LO = Left ovary. (Scale bar = 50 µm).

Mentions: As early as 1935, Witschi suggested that the left embryonic ovary contains more germ cells than the right, consistent with the obvious difference in development of these female organs (the right ovary does not develop to adulthood) [44]. To visualise germ cells in the gonads we performed in situ hybridisation in whole mounts and sections of gonads of female and male embryos at stage HH 35 (9 days’ incubation; [45]) for the germ cell marker, Cvh (Fig. 1A, 2A). As expected, sections through left and right ovaries revealed significant differences in Cvh-positive cell numbers: 61±30 per transverse section on the left and 2±4 on the right; p<0.001, n = 64 sections through 3 embryos; Fig. 3; see also Table 1). However, left-right differences were also found in the male: the average number of germ cells expressing Cvh in left and right male gonads was 21±16 and 11±11 respectively (p<0.001, n = 78 sections in 3 embryos, Fig. 3).


Sexually dimorphic and sex-independent left-right asymmetries in chicken embryonic gonads.

Intarapat S, Stern CD - PLoS ONE (2013)

Left-right asymmetric gene expression in male embryonic gonads: Cvh (A), cPouV (B), cNanog (C), cSox2 (D) and ERNI (E) positive cells are expressed in both left and right ovaries.Ovarian sections exhibit germ cells, Cvh (A’) and cPouV (B’), cNanog (C’), cSox2 (D’) and ERNI (E’) positive cells. Abbreviations: RO = Right ovary, LO = Left ovary. (Scale bar = 50 µm).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3716703&req=5

pone-0069893-g002: Left-right asymmetric gene expression in male embryonic gonads: Cvh (A), cPouV (B), cNanog (C), cSox2 (D) and ERNI (E) positive cells are expressed in both left and right ovaries.Ovarian sections exhibit germ cells, Cvh (A’) and cPouV (B’), cNanog (C’), cSox2 (D’) and ERNI (E’) positive cells. Abbreviations: RO = Right ovary, LO = Left ovary. (Scale bar = 50 µm).
Mentions: As early as 1935, Witschi suggested that the left embryonic ovary contains more germ cells than the right, consistent with the obvious difference in development of these female organs (the right ovary does not develop to adulthood) [44]. To visualise germ cells in the gonads we performed in situ hybridisation in whole mounts and sections of gonads of female and male embryos at stage HH 35 (9 days’ incubation; [45]) for the germ cell marker, Cvh (Fig. 1A, 2A). As expected, sections through left and right ovaries revealed significant differences in Cvh-positive cell numbers: 61±30 per transverse section on the left and 2±4 on the right; p<0.001, n = 64 sections through 3 embryos; Fig. 3; see also Table 1). However, left-right differences were also found in the male: the average number of germ cells expressing Cvh in left and right male gonads was 21±16 and 11±11 respectively (p<0.001, n = 78 sections in 3 embryos, Fig. 3).

Bottom Line: Expression is asymmetric in both sexes: at stage 35 the left gonad contains significantly more germ cells than the right.Other pluripotency-associated markers (PouV/Oct3/4, Nanog and Sox2) also show asymmetric expression (more expressing cells on the left) in both sexes, but this asymmetry is at least partly due to expression in stromal cells of the developing gonad, and the pattern is different for all the genes.Therefore germ cell and pluripotency-associated genes show both sex-dependent and independent left-right asymmetry and a complex pattern of expression.

View Article: PubMed Central - PubMed

Affiliation: Department of Anatomy, Faculty of Science, Mahidol University, Bangkok, Thailand.

ABSTRACT
Female birds develop asymmetric gonads: a functional ovary develops on the left, whereas the right gonad regresses. In males, however, testes develop on both sides. We examined the distribution of germ cells using Vasa/Cvh as a marker. Expression is asymmetric in both sexes: at stage 35 the left gonad contains significantly more germ cells than the right. A similar expression pattern is seen for expression of ERNI (Ens1), a gene expressed in chick embryonic stem cells while they self-renew, but downregulated upon differentiation. Other pluripotency-associated markers (PouV/Oct3/4, Nanog and Sox2) also show asymmetric expression (more expressing cells on the left) in both sexes, but this asymmetry is at least partly due to expression in stromal cells of the developing gonad, and the pattern is different for all the genes. Therefore germ cell and pluripotency-associated genes show both sex-dependent and independent left-right asymmetry and a complex pattern of expression.

Show MeSH
Related in: MedlinePlus