Limits...
Bridging the synaptic gap: neuroligins and neurexin I in Apis mellifera.

Biswas S, Russell RJ, Jackson CJ, Vidovic M, Ganeshina O, Oakeshott JG, Claudianos C - PLoS ONE (2008)

Bottom Line: Neurexin I and neuroligin expression was found in brain tissue, with expression present throughout development, and in most cases significantly up-regulated in adults.We show neuroligins and neurexins comprise a highly conserved molecular system with likely similar functional roles in insects as vertebrates, and with scope in the honeybee to generate substantial functional diversity through alternative splicing.Our study provides important prerequisite data for using the bee as a model for vertebrate synaptic development.

View Article: PubMed Central - PubMed

Affiliation: University of Queensland, Queensland Brain Institute, Brisbane, Queensland, Australia.

ABSTRACT
Vertebrate studies show neuroligins and neurexins are binding partners in a trans-synaptic cell adhesion complex, implicated in human autism and mental retardation disorders. Here we report a genetic analysis of homologous proteins in the honey bee. As in humans, the honeybee has five large (31-246 kb, up to 12 exons each) neuroligin genes, three of which are tightly clustered. RNA analysis of the neuroligin-3 gene reveals five alternatively spliced transcripts, generated through alternative use of exons encoding the cholinesterase-like domain. Whereas vertebrates have three neurexins the bee has just one gene named neurexin I (400 kb, 28 exons). However alternative isoforms of bee neurexin I are generated by differential use of 12 splice sites, mostly located in regions encoding LNS subdomains. Some of the splice variants of bee neurexin I resemble the vertebrate alpha- and beta-neurexins, albeit in vertebrates these forms are generated by alternative promoters. Novel splicing variations in the 3' region generate transcripts encoding alternative trans-membrane and PDZ domains. Another 3' splicing variation predicts soluble neurexin I isoforms. Neurexin I and neuroligin expression was found in brain tissue, with expression present throughout development, and in most cases significantly up-regulated in adults. Transcripts of neurexin I and one neuroligin tested were abundant in mushroom bodies, a higher order processing centre in the bee brain. We show neuroligins and neurexins comprise a highly conserved molecular system with likely similar functional roles in insects as vertebrates, and with scope in the honeybee to generate substantial functional diversity through alternative splicing. Our study provides important prerequisite data for using the bee as a model for vertebrate synaptic development.

Show MeSH

Related in: MedlinePlus

Developmental Expression Profiles of the Neuroligins and Neurexin I in Honeybee Brain.Honeybee neuroligin and neurexin I expression was assessed by quantitative real time PCR amplification. The ribosomal gene RPL8 was used as the housekeeping gene. Methodology for data analysis and the presentation of results was taken from Collins et al [104]; where by expression levels were normalised by subtraction against the threshold cycle of the RPL8. Collins et al [104] found RPL8 to be the best correlate with RNA concentration across varying developmental life stages and varying tissues of the honeybee. Expression levels were examined from whole larvae (5 day old); and brain tissue from pupae (stage P8 as outlined by Ganeshina et al [101]) 24 hour adult, 7 day adult and forager honeybees. Standards errors were negligible and less than +/−1.18 for all experimental results. The coloured lines illustrate the developmental expression profile of a single gene through development. Data points in columns illustrate the relative levels of neurexin I and neuroligin expression to one another at a particular stage of development. The developmental stage/gene with lowest expression relative to the control gene (neuroligin 1 at 7 days of age) was given an arbitrary expression level of 1. The data values are shown in Supplementary Data Table 3.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2570956&req=5

pone-0003542-g005: Developmental Expression Profiles of the Neuroligins and Neurexin I in Honeybee Brain.Honeybee neuroligin and neurexin I expression was assessed by quantitative real time PCR amplification. The ribosomal gene RPL8 was used as the housekeeping gene. Methodology for data analysis and the presentation of results was taken from Collins et al [104]; where by expression levels were normalised by subtraction against the threshold cycle of the RPL8. Collins et al [104] found RPL8 to be the best correlate with RNA concentration across varying developmental life stages and varying tissues of the honeybee. Expression levels were examined from whole larvae (5 day old); and brain tissue from pupae (stage P8 as outlined by Ganeshina et al [101]) 24 hour adult, 7 day adult and forager honeybees. Standards errors were negligible and less than +/−1.18 for all experimental results. The coloured lines illustrate the developmental expression profile of a single gene through development. Data points in columns illustrate the relative levels of neurexin I and neuroligin expression to one another at a particular stage of development. The developmental stage/gene with lowest expression relative to the control gene (neuroligin 1 at 7 days of age) was given an arbitrary expression level of 1. The data values are shown in Supplementary Data Table 3.

Mentions: Expression of neurexin I and the neuroligins was found throughout development, from larvae to adult life stages (Figure 5, Table 3). Expression of neurexin I and neuroligins 2, 3, 4 and 5 generally increases through development, with particularly pronounced up-regulation from pupal to adult stages. Neuroligin 3 increases about 9 fold from early larvae to newly emerged adults (female worker bees), while neurexin I, neuroligin 4 and neuroligin 5 expression increases approximately 25–40 fold over this period. The expression of both neuroligin 3 and 5 appears to drop slightly at one-week post adult emergence. Neuroligin 2 shows the greatest change through development, with a 140-fold increase in expression through early developmental to adult stages. At the other extreme, neuroligin 1 shows a consistent level of expression throughout development. It is also one of the most highly expressed neuroligins in the larval sample, although this could represent expression outside the central nervous system since whole larvae were analysed as opposed to only brain tissue at other developmental stages.


Bridging the synaptic gap: neuroligins and neurexin I in Apis mellifera.

Biswas S, Russell RJ, Jackson CJ, Vidovic M, Ganeshina O, Oakeshott JG, Claudianos C - PLoS ONE (2008)

Developmental Expression Profiles of the Neuroligins and Neurexin I in Honeybee Brain.Honeybee neuroligin and neurexin I expression was assessed by quantitative real time PCR amplification. The ribosomal gene RPL8 was used as the housekeeping gene. Methodology for data analysis and the presentation of results was taken from Collins et al [104]; where by expression levels were normalised by subtraction against the threshold cycle of the RPL8. Collins et al [104] found RPL8 to be the best correlate with RNA concentration across varying developmental life stages and varying tissues of the honeybee. Expression levels were examined from whole larvae (5 day old); and brain tissue from pupae (stage P8 as outlined by Ganeshina et al [101]) 24 hour adult, 7 day adult and forager honeybees. Standards errors were negligible and less than +/−1.18 for all experimental results. The coloured lines illustrate the developmental expression profile of a single gene through development. Data points in columns illustrate the relative levels of neurexin I and neuroligin expression to one another at a particular stage of development. The developmental stage/gene with lowest expression relative to the control gene (neuroligin 1 at 7 days of age) was given an arbitrary expression level of 1. The data values are shown in Supplementary Data Table 3.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2570956&req=5

pone-0003542-g005: Developmental Expression Profiles of the Neuroligins and Neurexin I in Honeybee Brain.Honeybee neuroligin and neurexin I expression was assessed by quantitative real time PCR amplification. The ribosomal gene RPL8 was used as the housekeeping gene. Methodology for data analysis and the presentation of results was taken from Collins et al [104]; where by expression levels were normalised by subtraction against the threshold cycle of the RPL8. Collins et al [104] found RPL8 to be the best correlate with RNA concentration across varying developmental life stages and varying tissues of the honeybee. Expression levels were examined from whole larvae (5 day old); and brain tissue from pupae (stage P8 as outlined by Ganeshina et al [101]) 24 hour adult, 7 day adult and forager honeybees. Standards errors were negligible and less than +/−1.18 for all experimental results. The coloured lines illustrate the developmental expression profile of a single gene through development. Data points in columns illustrate the relative levels of neurexin I and neuroligin expression to one another at a particular stage of development. The developmental stage/gene with lowest expression relative to the control gene (neuroligin 1 at 7 days of age) was given an arbitrary expression level of 1. The data values are shown in Supplementary Data Table 3.
Mentions: Expression of neurexin I and the neuroligins was found throughout development, from larvae to adult life stages (Figure 5, Table 3). Expression of neurexin I and neuroligins 2, 3, 4 and 5 generally increases through development, with particularly pronounced up-regulation from pupal to adult stages. Neuroligin 3 increases about 9 fold from early larvae to newly emerged adults (female worker bees), while neurexin I, neuroligin 4 and neuroligin 5 expression increases approximately 25–40 fold over this period. The expression of both neuroligin 3 and 5 appears to drop slightly at one-week post adult emergence. Neuroligin 2 shows the greatest change through development, with a 140-fold increase in expression through early developmental to adult stages. At the other extreme, neuroligin 1 shows a consistent level of expression throughout development. It is also one of the most highly expressed neuroligins in the larval sample, although this could represent expression outside the central nervous system since whole larvae were analysed as opposed to only brain tissue at other developmental stages.

Bottom Line: Neurexin I and neuroligin expression was found in brain tissue, with expression present throughout development, and in most cases significantly up-regulated in adults.We show neuroligins and neurexins comprise a highly conserved molecular system with likely similar functional roles in insects as vertebrates, and with scope in the honeybee to generate substantial functional diversity through alternative splicing.Our study provides important prerequisite data for using the bee as a model for vertebrate synaptic development.

View Article: PubMed Central - PubMed

Affiliation: University of Queensland, Queensland Brain Institute, Brisbane, Queensland, Australia.

ABSTRACT
Vertebrate studies show neuroligins and neurexins are binding partners in a trans-synaptic cell adhesion complex, implicated in human autism and mental retardation disorders. Here we report a genetic analysis of homologous proteins in the honey bee. As in humans, the honeybee has five large (31-246 kb, up to 12 exons each) neuroligin genes, three of which are tightly clustered. RNA analysis of the neuroligin-3 gene reveals five alternatively spliced transcripts, generated through alternative use of exons encoding the cholinesterase-like domain. Whereas vertebrates have three neurexins the bee has just one gene named neurexin I (400 kb, 28 exons). However alternative isoforms of bee neurexin I are generated by differential use of 12 splice sites, mostly located in regions encoding LNS subdomains. Some of the splice variants of bee neurexin I resemble the vertebrate alpha- and beta-neurexins, albeit in vertebrates these forms are generated by alternative promoters. Novel splicing variations in the 3' region generate transcripts encoding alternative trans-membrane and PDZ domains. Another 3' splicing variation predicts soluble neurexin I isoforms. Neurexin I and neuroligin expression was found in brain tissue, with expression present throughout development, and in most cases significantly up-regulated in adults. Transcripts of neurexin I and one neuroligin tested were abundant in mushroom bodies, a higher order processing centre in the bee brain. We show neuroligins and neurexins comprise a highly conserved molecular system with likely similar functional roles in insects as vertebrates, and with scope in the honeybee to generate substantial functional diversity through alternative splicing. Our study provides important prerequisite data for using the bee as a model for vertebrate synaptic development.

Show MeSH
Related in: MedlinePlus