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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 functions downstream of tra-2 and upstream of fem-3.Whole worm DAPI images were taken of young adults (L4+1 day) in the presence and absence of trd-1 RNAi. The top panel shows that the germlines of fem-3(lf) (strain, CB4034) mutants are normally feminized at the restrictive temperature of 25°C. trd-1 (RNAi) does not suppress this phenotype. In contrast, the feminized germline of tra-2(gf) animals (strain, CB3778) is significantly suppressed following trd-1 RNAi, with most germlines being masculinized. Sp indicates the region of post-meiotic sperm and Oo represents oocytes in diakinesis. Closed circles indicate unfertilized oocytes and the asterisk indicates the location of the vulva. Scale bar, 20 µm. Anterior is to the left and dorsal is up in all images.
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pone-0114998-g005: trd-1 functions downstream of tra-2 and upstream of fem-3.Whole worm DAPI images were taken of young adults (L4+1 day) in the presence and absence of trd-1 RNAi. The top panel shows that the germlines of fem-3(lf) (strain, CB4034) mutants are normally feminized at the restrictive temperature of 25°C. trd-1 (RNAi) does not suppress this phenotype. In contrast, the feminized germline of tra-2(gf) animals (strain, CB3778) is significantly suppressed following trd-1 RNAi, with most germlines being masculinized. Sp indicates the region of post-meiotic sperm and Oo represents oocytes in diakinesis. Closed circles indicate unfertilized oocytes and the asterisk indicates the location of the vulva. Scale bar, 20 µm. Anterior is to the left and dorsal is up in all images.

Mentions: The next obvious mutants to test were fem-3 and tra-2, whose activities need to be finely balanced in order to correctly regulate the switch between sperm and oocyte production. In addition, gain of function alleles are available for both fem-3 and tra-2, which makes epistasis experiments easier to interpret. fem-3(gf) mutants are masculinized, whereas tra-2(gf) mutants are feminized, but double fem-3(gf); tra-2(gf) mutants are fully fertile. In the case of tra-2(gf) mutants, RNAi of trd-1 suppressed the Fem phenotype in the majority of animals, giving the masculinized phenotype characteristic of trd-1 RNAi (Fig. 5, Table 2). Thus, trd-1 is likely to function downstream of tra-2. However, trd-1 RNAi did not suppress the feminization of fem-3(lf) mutants (Fig. 5), suggestive of trd-1 operating upstream of fem-3. Although trd-1 RNAi made no difference to fem-3(gf) mutants at the restrictive temperature (complete masculinization), we did notice a synergistic masculinization at the permissive temperature of 15°C. At this temperature fem-3(gf) mutants show only a very weakly penetrant masculinization phenotype (2%), which is enhanced to >90% in the absence of trd-1 (Table 3). Taken together, these data suggest that trd-1 is likely to act at the level of fem-3 in the germline sex determination pathway.


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 functions downstream of tra-2 and upstream of fem-3.Whole worm DAPI images were taken of young adults (L4+1 day) in the presence and absence of trd-1 RNAi. The top panel shows that the germlines of fem-3(lf) (strain, CB4034) mutants are normally feminized at the restrictive temperature of 25°C. trd-1 (RNAi) does not suppress this phenotype. In contrast, the feminized germline of tra-2(gf) animals (strain, CB3778) is significantly suppressed following trd-1 RNAi, with most germlines being masculinized. Sp indicates the region of post-meiotic sperm and Oo represents oocytes in diakinesis. Closed circles indicate unfertilized oocytes and the asterisk indicates the location of the vulva. Scale bar, 20 µm. Anterior is to the left and dorsal is up in all images.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4262444&req=5

pone-0114998-g005: trd-1 functions downstream of tra-2 and upstream of fem-3.Whole worm DAPI images were taken of young adults (L4+1 day) in the presence and absence of trd-1 RNAi. The top panel shows that the germlines of fem-3(lf) (strain, CB4034) mutants are normally feminized at the restrictive temperature of 25°C. trd-1 (RNAi) does not suppress this phenotype. In contrast, the feminized germline of tra-2(gf) animals (strain, CB3778) is significantly suppressed following trd-1 RNAi, with most germlines being masculinized. Sp indicates the region of post-meiotic sperm and Oo represents oocytes in diakinesis. Closed circles indicate unfertilized oocytes and the asterisk indicates the location of the vulva. Scale bar, 20 µm. Anterior is to the left and dorsal is up in all images.
Mentions: The next obvious mutants to test were fem-3 and tra-2, whose activities need to be finely balanced in order to correctly regulate the switch between sperm and oocyte production. In addition, gain of function alleles are available for both fem-3 and tra-2, which makes epistasis experiments easier to interpret. fem-3(gf) mutants are masculinized, whereas tra-2(gf) mutants are feminized, but double fem-3(gf); tra-2(gf) mutants are fully fertile. In the case of tra-2(gf) mutants, RNAi of trd-1 suppressed the Fem phenotype in the majority of animals, giving the masculinized phenotype characteristic of trd-1 RNAi (Fig. 5, Table 2). Thus, trd-1 is likely to function downstream of tra-2. However, trd-1 RNAi did not suppress the feminization of fem-3(lf) mutants (Fig. 5), suggestive of trd-1 operating upstream of fem-3. Although trd-1 RNAi made no difference to fem-3(gf) mutants at the restrictive temperature (complete masculinization), we did notice a synergistic masculinization at the permissive temperature of 15°C. At this temperature fem-3(gf) mutants show only a very weakly penetrant masculinization phenotype (2%), which is enhanced to >90% in the absence of trd-1 (Table 3). Taken together, these data suggest that trd-1 is likely to act at the level of fem-3 in the germline sex determination pathway.

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