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mab-31 and the TGF-beta pathway act in the ray lineage to pattern C. elegans male sensory rays.

Wong YF, Sheng Q, Chung JW, Chan JK, Chow KL - BMC Dev. Biol. (2010)

Bottom Line: Both mab-31 and sma-6 are required in ray lineage at the late larval stages.They act upstream of C. elegans Pax-6 homolog and repress its function.These findings suggested mab-31 is a key factor that can integrate TFG-beta signals in male sensory ray lineage to define organ identity.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Biology, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong.

ABSTRACT

Background: C. elegans TGF-beta-like Sma/Mab signaling pathway regulates both body size and sensory ray patterning. Most of the components in this pathway were initially identified by genetic screens based on the small body phenotype, and many of these mutants display sensory ray patterning defect. At the cellular level, little is known about how and where these components work although ray structural cell has been implicated as one of the targets. Based on the specific ray patterning abnormality, we aim to identify by RNAi approach additional components that function specifically in the ray lineage to elucidate the regulatory role of TGF-beta signaling in ray differentiation.

Result: We report here the characterization of a new member of the Sma/Mab pathway, mab-31, recovered from a genome-wide RNAi screen. mab-31 mutants showed ray cell cluster patterning defect and mis-specification of the ray identity. mab-31 encodes a nuclear protein expressed in descendants of ray precursor cells impacting on the ray cell's clustering properties, orientation of cell division plane, and fusion of structural cells. Genetic experiments also establish its relationship with other Sma/Mab pathway components and transcription factors acting upstream and downstream of the signaling event.

Conclusion: mab-31 function is indispensable in Sma/Mab signal recipient cells during sensory rays specification. Both mab-31 and sma-6 are required in ray lineage at the late larval stages. They act upstream of C. elegans Pax-6 homolog and repress its function. These findings suggested mab-31 is a key factor that can integrate TFG-beta signals in male sensory ray lineage to define organ identity.

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Epistatic analysis of Sma/Mab pathway in ray 6 specification. Frequency of ray fusion phenotypes (rays 6-7 fusion or rays 6-4 fusion) is shown in double mutants of mab-31 with those of Sma/Mab pathway (A) and with those showing rays 6-4 fusion phenotypes. In double mutants of mab-31 and mab-18 (E), only rays 6-4 fusion phenotype was observed, as compared with wild-type (B), mab-18 (C), and mab-31 (D) male tails. Ventral view for B-E. Scale bar = 20 μm.
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Figure 4: Epistatic analysis of Sma/Mab pathway in ray 6 specification. Frequency of ray fusion phenotypes (rays 6-7 fusion or rays 6-4 fusion) is shown in double mutants of mab-31 with those of Sma/Mab pathway (A) and with those showing rays 6-4 fusion phenotypes. In double mutants of mab-31 and mab-18 (E), only rays 6-4 fusion phenotype was observed, as compared with wild-type (B), mab-18 (C), and mab-31 (D) male tails. Ventral view for B-E. Scale bar = 20 μm.

Mentions: Several components in Sma/Mab pathway were shown to negatively regulate the mab-21 gene in ray patterning [5]. In mab-21 mutants, the ray 6 structural cell apparently undergoes a specific transformation into a ray 4 morphogenetic identity and ray 6 is fused with ray 4. Double mutant of mab-21 with either sma-6 or sma-4 resulted in rays 6-4 fusion phenotype, which mimicked the Mab-21 phenotype. We could also establish a similar epistatic relationship between mab-31 and the components in mab-21 pathway. In the double mutant of mab-31(tm2718); mab-21(bx53), only Mab-21 phenotype could be observed (Figure 4A). Thus the role of mab-31 is similar to Sma/Mab pathway, which negatively regulates mab-21 during the specification of ray 6.


mab-31 and the TGF-beta pathway act in the ray lineage to pattern C. elegans male sensory rays.

Wong YF, Sheng Q, Chung JW, Chan JK, Chow KL - BMC Dev. Biol. (2010)

Epistatic analysis of Sma/Mab pathway in ray 6 specification. Frequency of ray fusion phenotypes (rays 6-7 fusion or rays 6-4 fusion) is shown in double mutants of mab-31 with those of Sma/Mab pathway (A) and with those showing rays 6-4 fusion phenotypes. In double mutants of mab-31 and mab-18 (E), only rays 6-4 fusion phenotype was observed, as compared with wild-type (B), mab-18 (C), and mab-31 (D) male tails. Ventral view for B-E. Scale bar = 20 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2921377&req=5

Figure 4: Epistatic analysis of Sma/Mab pathway in ray 6 specification. Frequency of ray fusion phenotypes (rays 6-7 fusion or rays 6-4 fusion) is shown in double mutants of mab-31 with those of Sma/Mab pathway (A) and with those showing rays 6-4 fusion phenotypes. In double mutants of mab-31 and mab-18 (E), only rays 6-4 fusion phenotype was observed, as compared with wild-type (B), mab-18 (C), and mab-31 (D) male tails. Ventral view for B-E. Scale bar = 20 μm.
Mentions: Several components in Sma/Mab pathway were shown to negatively regulate the mab-21 gene in ray patterning [5]. In mab-21 mutants, the ray 6 structural cell apparently undergoes a specific transformation into a ray 4 morphogenetic identity and ray 6 is fused with ray 4. Double mutant of mab-21 with either sma-6 or sma-4 resulted in rays 6-4 fusion phenotype, which mimicked the Mab-21 phenotype. We could also establish a similar epistatic relationship between mab-31 and the components in mab-21 pathway. In the double mutant of mab-31(tm2718); mab-21(bx53), only Mab-21 phenotype could be observed (Figure 4A). Thus the role of mab-31 is similar to Sma/Mab pathway, which negatively regulates mab-21 during the specification of ray 6.

Bottom Line: Both mab-31 and sma-6 are required in ray lineage at the late larval stages.They act upstream of C. elegans Pax-6 homolog and repress its function.These findings suggested mab-31 is a key factor that can integrate TFG-beta signals in male sensory ray lineage to define organ identity.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Biology, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong.

ABSTRACT

Background: C. elegans TGF-beta-like Sma/Mab signaling pathway regulates both body size and sensory ray patterning. Most of the components in this pathway were initially identified by genetic screens based on the small body phenotype, and many of these mutants display sensory ray patterning defect. At the cellular level, little is known about how and where these components work although ray structural cell has been implicated as one of the targets. Based on the specific ray patterning abnormality, we aim to identify by RNAi approach additional components that function specifically in the ray lineage to elucidate the regulatory role of TGF-beta signaling in ray differentiation.

Result: We report here the characterization of a new member of the Sma/Mab pathway, mab-31, recovered from a genome-wide RNAi screen. mab-31 mutants showed ray cell cluster patterning defect and mis-specification of the ray identity. mab-31 encodes a nuclear protein expressed in descendants of ray precursor cells impacting on the ray cell's clustering properties, orientation of cell division plane, and fusion of structural cells. Genetic experiments also establish its relationship with other Sma/Mab pathway components and transcription factors acting upstream and downstream of the signaling event.

Conclusion: mab-31 function is indispensable in Sma/Mab signal recipient cells during sensory rays specification. Both mab-31 and sma-6 are required in ray lineage at the late larval stages. They act upstream of C. elegans Pax-6 homolog and repress its function. These findings suggested mab-31 is a key factor that can integrate TFG-beta signals in male sensory ray lineage to define organ identity.

Show MeSH
Related in: MedlinePlus