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The dnd RNA Identifies Germ Cell Origin and Migration in Olive Flounder (Paralichthys olivaceus).

Wang X, Liu Q, Xiao Y, Yang Y, Wang Y, Song Z, You F, An H, Xiao Z, Xu S, Ma D, Li J - Biomed Res Int (2015)

Bottom Line: The expression of Podnd during embryonic development at 16 different stages revealed that the relative expression of Podnd transcript fluctuated at a high level in the cleavage stages, gradually decreased through subsequent development, and reached the lowest at late gastrula stage till it was nearly undetectable.The Podnd transcripts localization and migration were similar to zebrafish.Further research on the specification migration mechanism of PGCs and the role of germ cell during gonadal development in olive flounder would improve our understanding of germline development.

View Article: PubMed Central - PubMed

Affiliation: Center of Biotechnology R&D, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China ; University of Chinese Academy of Sciences, Beijing 100049, China.

ABSTRACT
The present study obtained a germ cell-specific marker dead end (dnd) in olive flounder (Paralichthys olivaceus) named Podnd. The tissue-specific expressions of Podnd transcripts were present in testis and ovary but were not detectable in other somatic tissues detected. SISH showed that Podnd expressed only in germ cells at different developmental stages but not in surrounding somatic cells. The expression of Podnd during embryonic development at 16 different stages revealed that the relative expression of Podnd transcript fluctuated at a high level in the cleavage stages, gradually decreased through subsequent development, and reached the lowest at late gastrula stage till it was nearly undetectable. The Podnd transcripts localization and migration were similar to zebrafish. Further research on the specification migration mechanism of PGCs and the role of germ cell during gonadal development in olive flounder would improve our understanding of germline development.

No MeSH data available.


Related in: MedlinePlus

Distribution of Podnd transcripts from 2-cell stage to 2 days after hatching. Embryos were hybridized with Podnd antisense probe. Black arrows indicate Podnd transcript aggregated regions (dark purple). Dotted straight line indicates embryonic body axis. Dotted arrows indicate PGC migration direction. (a) 2-cell stage: Podnd transcripts are concentrated at the distal edge of the 1st cleavage furrow; (b) 4-cell stage: Podnd signals are located as four spots at the distal edge of the 1st and 2nd cleavage furrows; (c) 8-cell stage: Podnd transcripts are still at the distal edge of the first two cleavage furrows; (d) 16-cell stage: Podnd transcripts are migrating from cleavage furrows to the edge of cells, respectively; (e) 32-cell stage: Podnd-positive spots are distributed into four cells, respectively; (f) morula stage: Podnd transcripts are still in four cells; ((g1) and (g2)) blastula stage: Podnd-positive cells increase and are located adjacent to each other; ((Ga) and (Gb)) magnification of the boxed region in (g1), respectively; (h) top view of early gastrula stage: Podnd-positive cells are located in the marginal region of blastoderm. Black arrowheads: (i) top view of mid gastrula stage: Podnd-positive cells are located at germ ring; ((j1) and (j2)) dorsal and lateral view of mid and late gastrula stage, respectively: Podnd-positive cells move towards the dorsal side, and some cells still lie in the germ ring region; ((j3)–(j5)) lateral view of late gastrula stage, respectively. (j3) Podnd-positive cells scattered in anterior of the trunk mesoderm appeared to align along anterior of the body axes from being randomly oriented, (j4) Podnd-positive cells moved posterior-ward, and (j5) Podnd-positive cells aligned along both sides of the body axes in posterior of the trunk region. (k) Early somite stage: Podnd-positive cells aligned along both sides of the body axes. (l) Somite stage: Podnd-positive cells moved outward and aligned as two lines along both sides of the embryonic body in the trunk region; (m) heart beating stage: the Podnd-positive cells formed clusters above the hind gut in the presumptive genital ridge; (n) hatching stage: Podnd-positive cells cluster under the genital ridge, which are above the posterior end of the hind gut and below the somites on either side of the embryonic body. ((o1) and (p)) 1-2 d after hatching: Podnd-positive cells cluster in the presumptive genital ridge region at the posterior dorsal sides of gut; (o2) longitudinal section of 1 d larva hybridized with Podnd antisense probe: Podnd-positive cells cluster in the presumptive genital ridge region at the posterior dorsal sides of gut. (o3) Cross section of 1 d larva hybridized with Podnd antisense probe: the Podnd-positive cells still aligned at the genital ridge which was at the dorsal sides of the hind gut, ventral side of notochord. Scale bar: 100 µm.
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fig4: Distribution of Podnd transcripts from 2-cell stage to 2 days after hatching. Embryos were hybridized with Podnd antisense probe. Black arrows indicate Podnd transcript aggregated regions (dark purple). Dotted straight line indicates embryonic body axis. Dotted arrows indicate PGC migration direction. (a) 2-cell stage: Podnd transcripts are concentrated at the distal edge of the 1st cleavage furrow; (b) 4-cell stage: Podnd signals are located as four spots at the distal edge of the 1st and 2nd cleavage furrows; (c) 8-cell stage: Podnd transcripts are still at the distal edge of the first two cleavage furrows; (d) 16-cell stage: Podnd transcripts are migrating from cleavage furrows to the edge of cells, respectively; (e) 32-cell stage: Podnd-positive spots are distributed into four cells, respectively; (f) morula stage: Podnd transcripts are still in four cells; ((g1) and (g2)) blastula stage: Podnd-positive cells increase and are located adjacent to each other; ((Ga) and (Gb)) magnification of the boxed region in (g1), respectively; (h) top view of early gastrula stage: Podnd-positive cells are located in the marginal region of blastoderm. Black arrowheads: (i) top view of mid gastrula stage: Podnd-positive cells are located at germ ring; ((j1) and (j2)) dorsal and lateral view of mid and late gastrula stage, respectively: Podnd-positive cells move towards the dorsal side, and some cells still lie in the germ ring region; ((j3)–(j5)) lateral view of late gastrula stage, respectively. (j3) Podnd-positive cells scattered in anterior of the trunk mesoderm appeared to align along anterior of the body axes from being randomly oriented, (j4) Podnd-positive cells moved posterior-ward, and (j5) Podnd-positive cells aligned along both sides of the body axes in posterior of the trunk region. (k) Early somite stage: Podnd-positive cells aligned along both sides of the body axes. (l) Somite stage: Podnd-positive cells moved outward and aligned as two lines along both sides of the embryonic body in the trunk region; (m) heart beating stage: the Podnd-positive cells formed clusters above the hind gut in the presumptive genital ridge; (n) hatching stage: Podnd-positive cells cluster under the genital ridge, which are above the posterior end of the hind gut and below the somites on either side of the embryonic body. ((o1) and (p)) 1-2 d after hatching: Podnd-positive cells cluster in the presumptive genital ridge region at the posterior dorsal sides of gut; (o2) longitudinal section of 1 d larva hybridized with Podnd antisense probe: Podnd-positive cells cluster in the presumptive genital ridge region at the posterior dorsal sides of gut. (o3) Cross section of 1 d larva hybridized with Podnd antisense probe: the Podnd-positive cells still aligned at the genital ridge which was at the dorsal sides of the hind gut, ventral side of notochord. Scale bar: 100 µm.

Mentions: The localization of Podnd transcripts was investigated by WISH during embryogenesis from 2-cell stage to 2 days after hatching to reveal the origin and migration of PGCs. At the 2-cell stage (Figures 4(a) and 5(a)), Podnd mRNA was detected at either end of the first cleavage furrow. At the 4-cell (Figures 4(b) and 5(b)) and 8-cell (Figures 4(c) and 5(c)) stages, mRNA aggregations had split into four clusters which remained located at the end of the first and second cleavage furrows. As the embryo developed to 32-cell stage (Figures 4(e) and 5(e)), the signals aggregated into four single blastomeres and formed presumptive PGCs. At morula stage (Figures 4(f) and 5(f)), the four Podnd-positive cells were still located at the margin of blastoderm. During the blastula stage (Figures 4(g1), 4(g2), and 5(g)), the Podnd-positive cells increased from one to two and the sister cells were located adjacent to each other at every positive area and then formed PGCs.


The dnd RNA Identifies Germ Cell Origin and Migration in Olive Flounder (Paralichthys olivaceus).

Wang X, Liu Q, Xiao Y, Yang Y, Wang Y, Song Z, You F, An H, Xiao Z, Xu S, Ma D, Li J - Biomed Res Int (2015)

Distribution of Podnd transcripts from 2-cell stage to 2 days after hatching. Embryos were hybridized with Podnd antisense probe. Black arrows indicate Podnd transcript aggregated regions (dark purple). Dotted straight line indicates embryonic body axis. Dotted arrows indicate PGC migration direction. (a) 2-cell stage: Podnd transcripts are concentrated at the distal edge of the 1st cleavage furrow; (b) 4-cell stage: Podnd signals are located as four spots at the distal edge of the 1st and 2nd cleavage furrows; (c) 8-cell stage: Podnd transcripts are still at the distal edge of the first two cleavage furrows; (d) 16-cell stage: Podnd transcripts are migrating from cleavage furrows to the edge of cells, respectively; (e) 32-cell stage: Podnd-positive spots are distributed into four cells, respectively; (f) morula stage: Podnd transcripts are still in four cells; ((g1) and (g2)) blastula stage: Podnd-positive cells increase and are located adjacent to each other; ((Ga) and (Gb)) magnification of the boxed region in (g1), respectively; (h) top view of early gastrula stage: Podnd-positive cells are located in the marginal region of blastoderm. Black arrowheads: (i) top view of mid gastrula stage: Podnd-positive cells are located at germ ring; ((j1) and (j2)) dorsal and lateral view of mid and late gastrula stage, respectively: Podnd-positive cells move towards the dorsal side, and some cells still lie in the germ ring region; ((j3)–(j5)) lateral view of late gastrula stage, respectively. (j3) Podnd-positive cells scattered in anterior of the trunk mesoderm appeared to align along anterior of the body axes from being randomly oriented, (j4) Podnd-positive cells moved posterior-ward, and (j5) Podnd-positive cells aligned along both sides of the body axes in posterior of the trunk region. (k) Early somite stage: Podnd-positive cells aligned along both sides of the body axes. (l) Somite stage: Podnd-positive cells moved outward and aligned as two lines along both sides of the embryonic body in the trunk region; (m) heart beating stage: the Podnd-positive cells formed clusters above the hind gut in the presumptive genital ridge; (n) hatching stage: Podnd-positive cells cluster under the genital ridge, which are above the posterior end of the hind gut and below the somites on either side of the embryonic body. ((o1) and (p)) 1-2 d after hatching: Podnd-positive cells cluster in the presumptive genital ridge region at the posterior dorsal sides of gut; (o2) longitudinal section of 1 d larva hybridized with Podnd antisense probe: Podnd-positive cells cluster in the presumptive genital ridge region at the posterior dorsal sides of gut. (o3) Cross section of 1 d larva hybridized with Podnd antisense probe: the Podnd-positive cells still aligned at the genital ridge which was at the dorsal sides of the hind gut, ventral side of notochord. Scale bar: 100 µm.
© Copyright Policy - open-access
Related In: Results  -  Collection

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fig4: Distribution of Podnd transcripts from 2-cell stage to 2 days after hatching. Embryos were hybridized with Podnd antisense probe. Black arrows indicate Podnd transcript aggregated regions (dark purple). Dotted straight line indicates embryonic body axis. Dotted arrows indicate PGC migration direction. (a) 2-cell stage: Podnd transcripts are concentrated at the distal edge of the 1st cleavage furrow; (b) 4-cell stage: Podnd signals are located as four spots at the distal edge of the 1st and 2nd cleavage furrows; (c) 8-cell stage: Podnd transcripts are still at the distal edge of the first two cleavage furrows; (d) 16-cell stage: Podnd transcripts are migrating from cleavage furrows to the edge of cells, respectively; (e) 32-cell stage: Podnd-positive spots are distributed into four cells, respectively; (f) morula stage: Podnd transcripts are still in four cells; ((g1) and (g2)) blastula stage: Podnd-positive cells increase and are located adjacent to each other; ((Ga) and (Gb)) magnification of the boxed region in (g1), respectively; (h) top view of early gastrula stage: Podnd-positive cells are located in the marginal region of blastoderm. Black arrowheads: (i) top view of mid gastrula stage: Podnd-positive cells are located at germ ring; ((j1) and (j2)) dorsal and lateral view of mid and late gastrula stage, respectively: Podnd-positive cells move towards the dorsal side, and some cells still lie in the germ ring region; ((j3)–(j5)) lateral view of late gastrula stage, respectively. (j3) Podnd-positive cells scattered in anterior of the trunk mesoderm appeared to align along anterior of the body axes from being randomly oriented, (j4) Podnd-positive cells moved posterior-ward, and (j5) Podnd-positive cells aligned along both sides of the body axes in posterior of the trunk region. (k) Early somite stage: Podnd-positive cells aligned along both sides of the body axes. (l) Somite stage: Podnd-positive cells moved outward and aligned as two lines along both sides of the embryonic body in the trunk region; (m) heart beating stage: the Podnd-positive cells formed clusters above the hind gut in the presumptive genital ridge; (n) hatching stage: Podnd-positive cells cluster under the genital ridge, which are above the posterior end of the hind gut and below the somites on either side of the embryonic body. ((o1) and (p)) 1-2 d after hatching: Podnd-positive cells cluster in the presumptive genital ridge region at the posterior dorsal sides of gut; (o2) longitudinal section of 1 d larva hybridized with Podnd antisense probe: Podnd-positive cells cluster in the presumptive genital ridge region at the posterior dorsal sides of gut. (o3) Cross section of 1 d larva hybridized with Podnd antisense probe: the Podnd-positive cells still aligned at the genital ridge which was at the dorsal sides of the hind gut, ventral side of notochord. Scale bar: 100 µm.
Mentions: The localization of Podnd transcripts was investigated by WISH during embryogenesis from 2-cell stage to 2 days after hatching to reveal the origin and migration of PGCs. At the 2-cell stage (Figures 4(a) and 5(a)), Podnd mRNA was detected at either end of the first cleavage furrow. At the 4-cell (Figures 4(b) and 5(b)) and 8-cell (Figures 4(c) and 5(c)) stages, mRNA aggregations had split into four clusters which remained located at the end of the first and second cleavage furrows. As the embryo developed to 32-cell stage (Figures 4(e) and 5(e)), the signals aggregated into four single blastomeres and formed presumptive PGCs. At morula stage (Figures 4(f) and 5(f)), the four Podnd-positive cells were still located at the margin of blastoderm. During the blastula stage (Figures 4(g1), 4(g2), and 5(g)), the Podnd-positive cells increased from one to two and the sister cells were located adjacent to each other at every positive area and then formed PGCs.

Bottom Line: The expression of Podnd during embryonic development at 16 different stages revealed that the relative expression of Podnd transcript fluctuated at a high level in the cleavage stages, gradually decreased through subsequent development, and reached the lowest at late gastrula stage till it was nearly undetectable.The Podnd transcripts localization and migration were similar to zebrafish.Further research on the specification migration mechanism of PGCs and the role of germ cell during gonadal development in olive flounder would improve our understanding of germline development.

View Article: PubMed Central - PubMed

Affiliation: Center of Biotechnology R&D, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China ; University of Chinese Academy of Sciences, Beijing 100049, China.

ABSTRACT
The present study obtained a germ cell-specific marker dead end (dnd) in olive flounder (Paralichthys olivaceus) named Podnd. The tissue-specific expressions of Podnd transcripts were present in testis and ovary but were not detectable in other somatic tissues detected. SISH showed that Podnd expressed only in germ cells at different developmental stages but not in surrounding somatic cells. The expression of Podnd during embryonic development at 16 different stages revealed that the relative expression of Podnd transcript fluctuated at a high level in the cleavage stages, gradually decreased through subsequent development, and reached the lowest at late gastrula stage till it was nearly undetectable. The Podnd transcripts localization and migration were similar to zebrafish. Further research on the specification migration mechanism of PGCs and the role of germ cell during gonadal development in olive flounder would improve our understanding of germline development.

No MeSH data available.


Related in: MedlinePlus