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The C. elegans TPR Containing Protein, TRD-1, Regulates Cell Fate Choice in the Developing Germ Line and Epidermis.

Hughes S, Wilkinson H, Gilbert SP, Kishida M, Ding SS, Woollard A - PLoS ONE (2014)

Bottom Line: In the germline, stem cells adopt one of three possible fates: mitotic cell cycle, or gamete formation via meiosis, producing either sperm or oocytes.In the epidermis, the stem cell-like seam cells divide asymmetrically, with the daughters taking on either a proliferative (seam) or differentiated (hypodermal or neuronal) fate.We show that trd-1(RNAi) and mutant animals have fewer seam cells as a result of inappropriate differentiation towards the hypodermal fate.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry, University of Oxford, Oxford, United Kingdom.

ABSTRACT
Correct cell fate choice is crucial in development. In post-embryonic development of the hermaphroditic Caenorhabitis elegans, distinct cell fates must be adopted in two diverse tissues. In the germline, stem cells adopt one of three possible fates: mitotic cell cycle, or gamete formation via meiosis, producing either sperm or oocytes. In the epidermis, the stem cell-like seam cells divide asymmetrically, with the daughters taking on either a proliferative (seam) or differentiated (hypodermal or neuronal) fate. We have isolated a novel conserved C. elegans tetratricopeptide repeat containing protein, TRD-1, which is essential for cell fate determination in both the germline and the developing epidermis and has homologs in other species, including humans (TTC27). We show that trd-1(RNAi) and mutant animals have fewer seam cells as a result of inappropriate differentiation towards the hypodermal fate. In the germline, trd-1 RNAi results in a strong masculinization phenotype, as well as defects in the mitosis to meiosis switch. Our data suggests that trd-1 acts downstream of tra-2 but upstream of fem-3 in the germline sex determination pathway, and exhibits a constellation of phenotypes in common with other Mog (masculinization of germline) mutants. Thus, trd-1 is a new player in both the somatic and germline cell fate determination machinery, suggestive of a novel molecular connection between the development of these two diverse tissues.

No MeSH data available.


Related in: MedlinePlus

trd-1 RNAi results in a masculinized germline.(A) A representative (i) DIC and (ii) DAPI image of one proximal gonad arm in a wild type animal. The pachytene region and the presence of oocytes in diakinesis (open circles) are clearly observed in young adults. The condensed chromosomes are clearly visible in the DAPI image (asterisks). Oocytes are pushed through the spermatheca (Sp) to become fertilized embryos (closed circles). (B) Representative (i) DIC and (ii) DAPI images of a young adult animal exposed to trd-1 RNAi. A masculinized germline, or Mog phenotype, is clearly observed. No oocytes are seen, however there is an extended region of on-going sperm production (black line) containing DAPI staining characteristic of sperm (white line). In all images anterior is to the left and dorsal to the bottom. Scale bar, 20 µm. (C) (i) Wild type whip-like tail tip. (ii) Animals exposed to trd-1 RNAi also have whip-like tail tips, suggesting no somatic sexual transformation. Scale bar, 20 µm. Anterior is to the left and dorsal up in all panels.
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pone-0114998-g004: trd-1 RNAi results in a masculinized germline.(A) A representative (i) DIC and (ii) DAPI image of one proximal gonad arm in a wild type animal. The pachytene region and the presence of oocytes in diakinesis (open circles) are clearly observed in young adults. The condensed chromosomes are clearly visible in the DAPI image (asterisks). Oocytes are pushed through the spermatheca (Sp) to become fertilized embryos (closed circles). (B) Representative (i) DIC and (ii) DAPI images of a young adult animal exposed to trd-1 RNAi. A masculinized germline, or Mog phenotype, is clearly observed. No oocytes are seen, however there is an extended region of on-going sperm production (black line) containing DAPI staining characteristic of sperm (white line). In all images anterior is to the left and dorsal to the bottom. Scale bar, 20 µm. (C) (i) Wild type whip-like tail tip. (ii) Animals exposed to trd-1 RNAi also have whip-like tail tips, suggesting no somatic sexual transformation. Scale bar, 20 µm. Anterior is to the left and dorsal up in all panels.

Mentions: Given the strong expression of trd-1::gfp we observed in the gonad, we investigated possible roles for trd-1 in germline development. The most striking phenotype observed in trd-1(RNAi) animals was a significant increase in the amount of sperm and absence of oocytes. DAPI staining of wild type adult (L4+1 day) animals showed developing oocytes in the proximal gonad, which pass through the spermatheca to be fertilized (Fig. 4A). In contrast, in approximately 80% of trd-1(RNAi) gonads (n = >100) we observed a complete absence of oocytes with a vast increase in the number of sperm (Fig. 4B). Western blotting confirmed that in trd-1(RNAi) animals, there is a greater amount of sperm present compared to wild type (S2 Figure). Indeed, the MSP levels of trd-1(RNAi) animals are elevated, although not to the same extent as the completely masculinized fem-3(gf) mutant (S2 Figure). In contrast to the severe germline masculinization of trd-1(RNAi) animals, no somatic masculinization was evident. The hermaphrodite tail of both control and trd-1 RNAi animals has the simple whip-like structure characteristic of female somatic development (Fig. 4C). We conclude that removal of trd-1 results in a masculinization of germline, or Mog, phenotype, strongly indicative of a role for trd-1 in regulating the spermatogenesis-oogenesis switch, promoting oogenesis.


The C. elegans TPR Containing Protein, TRD-1, Regulates Cell Fate Choice in the Developing Germ Line and Epidermis.

Hughes S, Wilkinson H, Gilbert SP, Kishida M, Ding SS, Woollard A - PLoS ONE (2014)

trd-1 RNAi results in a masculinized germline.(A) A representative (i) DIC and (ii) DAPI image of one proximal gonad arm in a wild type animal. The pachytene region and the presence of oocytes in diakinesis (open circles) are clearly observed in young adults. The condensed chromosomes are clearly visible in the DAPI image (asterisks). Oocytes are pushed through the spermatheca (Sp) to become fertilized embryos (closed circles). (B) Representative (i) DIC and (ii) DAPI images of a young adult animal exposed to trd-1 RNAi. A masculinized germline, or Mog phenotype, is clearly observed. No oocytes are seen, however there is an extended region of on-going sperm production (black line) containing DAPI staining characteristic of sperm (white line). In all images anterior is to the left and dorsal to the bottom. Scale bar, 20 µm. (C) (i) Wild type whip-like tail tip. (ii) Animals exposed to trd-1 RNAi also have whip-like tail tips, suggesting no somatic sexual transformation. Scale bar, 20 µm. Anterior is to the left and dorsal up in all panels.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4262444&req=5

pone-0114998-g004: trd-1 RNAi results in a masculinized germline.(A) A representative (i) DIC and (ii) DAPI image of one proximal gonad arm in a wild type animal. The pachytene region and the presence of oocytes in diakinesis (open circles) are clearly observed in young adults. The condensed chromosomes are clearly visible in the DAPI image (asterisks). Oocytes are pushed through the spermatheca (Sp) to become fertilized embryos (closed circles). (B) Representative (i) DIC and (ii) DAPI images of a young adult animal exposed to trd-1 RNAi. A masculinized germline, or Mog phenotype, is clearly observed. No oocytes are seen, however there is an extended region of on-going sperm production (black line) containing DAPI staining characteristic of sperm (white line). In all images anterior is to the left and dorsal to the bottom. Scale bar, 20 µm. (C) (i) Wild type whip-like tail tip. (ii) Animals exposed to trd-1 RNAi also have whip-like tail tips, suggesting no somatic sexual transformation. Scale bar, 20 µm. Anterior is to the left and dorsal up in all panels.
Mentions: Given the strong expression of trd-1::gfp we observed in the gonad, we investigated possible roles for trd-1 in germline development. The most striking phenotype observed in trd-1(RNAi) animals was a significant increase in the amount of sperm and absence of oocytes. DAPI staining of wild type adult (L4+1 day) animals showed developing oocytes in the proximal gonad, which pass through the spermatheca to be fertilized (Fig. 4A). In contrast, in approximately 80% of trd-1(RNAi) gonads (n = >100) we observed a complete absence of oocytes with a vast increase in the number of sperm (Fig. 4B). Western blotting confirmed that in trd-1(RNAi) animals, there is a greater amount of sperm present compared to wild type (S2 Figure). Indeed, the MSP levels of trd-1(RNAi) animals are elevated, although not to the same extent as the completely masculinized fem-3(gf) mutant (S2 Figure). In contrast to the severe germline masculinization of trd-1(RNAi) animals, no somatic masculinization was evident. The hermaphrodite tail of both control and trd-1 RNAi animals has the simple whip-like structure characteristic of female somatic development (Fig. 4C). We conclude that removal of trd-1 results in a masculinization of germline, or Mog, phenotype, strongly indicative of a role for trd-1 in regulating the spermatogenesis-oogenesis switch, promoting oogenesis.

Bottom Line: In the germline, stem cells adopt one of three possible fates: mitotic cell cycle, or gamete formation via meiosis, producing either sperm or oocytes.In the epidermis, the stem cell-like seam cells divide asymmetrically, with the daughters taking on either a proliferative (seam) or differentiated (hypodermal or neuronal) fate.We show that trd-1(RNAi) and mutant animals have fewer seam cells as a result of inappropriate differentiation towards the hypodermal fate.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry, University of Oxford, Oxford, United Kingdom.

ABSTRACT
Correct cell fate choice is crucial in development. In post-embryonic development of the hermaphroditic Caenorhabitis elegans, distinct cell fates must be adopted in two diverse tissues. In the germline, stem cells adopt one of three possible fates: mitotic cell cycle, or gamete formation via meiosis, producing either sperm or oocytes. In the epidermis, the stem cell-like seam cells divide asymmetrically, with the daughters taking on either a proliferative (seam) or differentiated (hypodermal or neuronal) fate. We have isolated a novel conserved C. elegans tetratricopeptide repeat containing protein, TRD-1, which is essential for cell fate determination in both the germline and the developing epidermis and has homologs in other species, including humans (TTC27). We show that trd-1(RNAi) and mutant animals have fewer seam cells as a result of inappropriate differentiation towards the hypodermal fate. In the germline, trd-1 RNAi results in a strong masculinization phenotype, as well as defects in the mitosis to meiosis switch. Our data suggests that trd-1 acts downstream of tra-2 but upstream of fem-3 in the germline sex determination pathway, and exhibits a constellation of phenotypes in common with other Mog (masculinization of germline) mutants. Thus, trd-1 is a new player in both the somatic and germline cell fate determination machinery, suggestive of a novel molecular connection between the development of these two diverse tissues.

No MeSH data available.


Related in: MedlinePlus