A novel missense mutation in the gene encoding major intrinsic protein (MIP) in a Giant panda with unilateral cataract formation

Background Cataracts are defects of the lens that cause progressive visual impairment and ultimately blindness in many vertebrate species. Most cataracts are age-related, but up to one third have an underlying genetic cause. Cataracts are common in captive zoo animals, but it is often unclear whether these are congenital or acquired (age-related) lesions. Results Here we used a functional candidate gene screening approach to identify mutations associated with cataracts in a captive giant panda (Ailuropoda melanoleuca). We screened 11 genes often associated with human cataracts and identified a novel missense mutation (c.686G > A) in the MIP gene encoding major intrinsic protein. This is expressed in the lens and normally accumulates in the plasma membrane of lens fiber cells, where it plays an important role in fluid transport and cell adhesion. The mutation causes the replacement of serine with asparagine (p.S229N) in the C-terminal tail of the protein, and modeling predicts that the mutation induces conformational changes that may interfere with lens permeability and cell–cell interactions. Conclusion The c.686G > A mutation was found in a captive giant panda with a unilateral cataract but not in 18 controls from diverse regions in China, suggesting it is most likely a genuine disease-associated mutation rather than a single-nucleotide polymorphism. The mutation could therefore serve as a new genetic marker to predict the risk of congenital cataracts in captive giant pandas.

A Novel Missense Mutation in the Gene Encoding Major Intrinsic Protein (MIP) in a Giant Panda with Unilateral Cataract Formation

Background: Cataracts are defects of the lens that cause progressive visual impairment and ultimately blindness in many vertebrate species. Most cataracts are age-related, but up to one third have an underlying genetic cause. Cataracts are common in captive zoo animals, but it is often unclear whether these are congenital or acquired (age-related) lesions. Results: Here we used a functional candidate gene screening approach to identify mutations associated with cataracts in a captive giant panda (Ailuropoda melanoleuca). We screened 11 genes often associated with human cataracts and identified a novel missense mutation (c.686G>A) in the MIP gene encoding major intrinsic protein. This is expressed in the lens and normally accumulates in the plasma membrane of lens fiber cells, where it plays an important role in fluid transport and cell adhesion. The mutation causes the replacement of serine with asparagine (p.S229N) in the C-terminal tail of the protein, and modeling predicts that the mutation induces conformational changes that may interfere with lens permeability and cell–cell interactions.Conclusion: The c.686G>A mutation was found in a captive giant panda with a unilateral cataract but not in 18 controls from diverse regions in China, suggesting it is most likely a genuine disease-associated mutation rather than a single-nucleotide polymorphism. The mutation could therefore serve as a new genetic marker to predict the risk of congenital cataracts in captive giant pandas.

MtNIP5;1, a novel Medicago truncatula boron diffusion facilitator induced under deficiency

Background: Legumes comprise important crops that offer major agronomic benefits, including the capacity of establishing symbiosis with rhizobia, fixing atmospheric N2. It has been proven that legumes are particularly susceptible to boron (B) stress, which leads to important yield penalties. Boron (B) deficiency or toxicity in plants causes the inhibition of growth and an altered development. Under such conditions, the participation of two distinct protein families (the major intrinsic protein family MIP and the Boron transporter family BOR) is required to minimize detrimental effects caused by B stress. However, in legumes, little is known about the transport mechanisms responsible for B uptake and distribution, especially under deficiency. Results: A Medicago truncatula protein, MtNIP5;1 (Medtr1g097840) (homologous to the Arabidopsis thaliana AtNIP5;1) was identified as a novel legume B transporter involved in B uptake under deficiency. Further analyses revealed that this M. truncatula aquaporin expression was boron-regulated in roots, being induced under deficiency and repressed under toxicity. It localizes at the plasma membrane of root epidermal cells and in nodules, where B plays pivotal roles in symbiosis. Furthermore, the partial complementation of the nip5;1-1 A. thaliana mutant phenotype under B deficiency supports a functional role of MtNIP5;1 as a B transporter in this legume model plant. Conclusions: The results here presented support a functional role of MtNIP5;1 in B uptake under deficiency and provides new insights into B transport mechanisms in legume species.

MtNIP5;1, a novel Medicago truncatula boron diffusion facilitator induced under deficiency

Background Legumes comprise important crops that offer major agronomic benefits, including the capacity of establishing symbiosis with rhizobia, fixing atmospheric N2. It has been proven that legumes are particularly susceptible to boron (B) stress, which leads to important yield penalties. Boron (B) deficiency or toxicity in plants causes the inhibition of growth and an altered development. Under such conditions, the participation of two distinct protein families (the major intrinsic protein family MIP and the Boron transporter family BOR) is required to minimize detrimental effects caused by B stress. However, in legumes, little is known about the transport mechanisms responsible for B uptake and distribution, especially under deficiency. Results A Medicago truncatula protein, MtNIP5;1 (Medtr1g097840) (homologous to the Arabidopsis thaliana AtNIP5;1) was identified as a novel legume B transporter involved in B uptake under deficiency. Further analyses revealed that this M. truncatula aquaporin expression was boron-regulated in roots, being induced under deficiency and repressed under toxicity. It localizes at the plasma membrane of root epidermal cells and in nodules, where B plays pivotal roles in symbiosis. Furthermore, the partial complementation of the nip5;1–1 A. thaliana mutant phenotype under B deficiency supports a functional role of MtNIP5;1 as a B transporter in this legume model plant. Conclusions The results here presented support a functional role of MtNIP5;1 in B uptake under deficiency and provides new insights into B transport mechanisms in legume species.

Identification of aquaporin markers in Solanum melongena for water stress response

Aim: The study focused on identifying markers linked to aquaporin genes from the expressed regions of S. melongena using bioinformatics applications. Methodology: The EST collections were explored for identification of aquaporin markers for water stress response using comparative analysis and in-house developed repeat motif detection program. An algorithm was developed to generate repeat motifs which can be effectively used for collecting EST of S. melongena to filter the sequences having repeat motifs for further analysis. Results: From the results generated, the 22 potential sequences with the markers were found to be associated with aquaporin proteins. The detected repeat motifs are inherent part of markers and these markers are found to be evolutionarily conserved and associated with aquaporin proteins. Hence, identifying markers for the presence of aquaporin proteins play an important role in water diffusion across cell membranes in plants. Interpretation: Identifying aquaporin markers are useful for plant breeders for developing water stress tolerant crops during elevated temperatures. These markers are linked to water channel proteins that belong to superfamily Major Intrinsic Protein, that primarily plays an important role in conduction of water in plants.

MtNIP5;1, a novel Medicago truncatula boron diffusion facilitator induced under deficiency

Background: Legumes comprise important crops that offer major agronomic benefits, including the capacity of establishing symbiosis with rhizobia, fixing atmospheric N2. It has been proven that legumes are particularly susceptible to boron (B) stress, which leads to important yield penalties. Boron (B) deficiency or toxicity in plants causes the inhibition of growth and an altered development. Under such conditions, the participation of two distinct protein families (the major intrinsic protein family MIP and the Boron transporter family BOR) is required to minimize detrimental effects caused by B stress. However, in legumes, little is known about the transport mechanisms responsible for B uptake and distribution, especially under deficiency. Results: A Medicago truncatula protein, MtNIP5;1 (Medtr1g097840) (homologous to the Arabidopsis thaliana AtNIP5;1) was identified as a novel legume B transporter involved in B uptake under deficiency. Further analyses revealed that this M. truncatula aquaporin expression was boron-regulated in roots, being induced under deficiency and repressed under toxicity. It localizes at the plasma membrane of root epidermal cells and in nodules, where B plays pivotal roles in symbiosis. Furthermore, the partial complementation of the nip5;1-1 A. thaliana mutant phenotype under B deficiency supports a functional role of MtNIP5;1 as a B transporter in this legume model plant. Conclusions: The results here presented support a functional role of MtNIP5;1 in B uptake under deficiency and provides new insights into B transport mechanisms in legume species.

A Novel Missense Mutation in the Gene Encoding Major Intrinsic Protein (MIP) in a Giant Panda with Cataracts

Background: Cataracts are defects of the lens that cause progressive visual impairment and ultimately blindness in many vertebrate species. Most cataracts are age-related, but up to one third have an underlying genetic cause. Cataracts are common in captive zoo animals, but it is often unclear whether these are congenital or sporadic acquired (age-related) lesions. Results: Here we used a functional candidate gene- screening approach to identify mutations associated with cataracts in a captive giant panda (Ailuropoda melanoleuca). We screened 11 genes often associated with human cataracts and identified a novel missense mutation (c.686G>A) in the MIP gene encoding major intrinsic protein. , whichThis is expressed in the lens and normally accumulates in the plasma membrane of lens fiber cells, where it plays an important role in fluid transport and cell adhesion. The mutation causes the replacement of serine with asparagine (p.229S>Np.S229N) in the C-terminal tail of the protein, and modeling revealed predicts that the mutation- induced induces conformational changes that may interfere with lens permeability and cell–cell interactions. Conclusion: The c.686G>A mutation was found in a captive giant panda with a unilateral cataract but not in 18 controls from diverse regions of in China, suggesting that c.686G>Ait is likely to bemost likely a genuine disease-causing associated mutation rather than a single-nucleotide polymorphism 5 regions was used in this research. Conclusions: The c.686G>A mutation was not found in healthy pandas, suggesting itThe mutation could therefore serve as a new genetic marker to predict the risk of congenital cataracts in captive giant pandas.

A Novel Missense Mutation in the Gene Encoding Major Intrinsic Protein (MIP) in a Giant Panda with Cataracts

Background : Cataracts are defects of the lens that cause progressive visual impairment and ultimately blindness in many vertebrate species. Most cataracts are age-related, but up to one third have an underlying genetic cause. Cataracts are common in captive zoo animals, but it is often unclear whether these are congenital or sporadic (age-related) lesions.Results: Here we used a functional candidate gene-screening approach to identify mutations associated with cataracts in a captive giant panda ( Ailuropoda melanoleuca ). We identified a novel missense mutation ( c.686G>A) in the MIP gene encoding major intrinsic protein, which is expressed in the lens and normally accumulates in the plasma membrane of lens fiber cells, where it plays an important role in fluid transport and cell adhesion. The mutation causes the replacement of serine with asparagine ( p.229S>N ) in the C-terminal tail of the protein, and modeling revealed that mutation-induced conformational changes may interfere with lens permeability and cell–cell interactions.Conclusions: The mutation was not found in healthy pandas, suggesting it could serve as a new informative marker to predict the risk of congenital cataracts in captive giant pandas.