1
|
Yang H, Xu Y, Yuan Y, Liu X, Zhang J, Li J, Zhang R, Cao J, Cheng T, Liu C. Identification and function of the Pax gene Bmgsb in the silk gland of Bombyx mori. INSECT MOLECULAR BIOLOGY 2024; 33:173-184. [PMID: 38238257 DOI: 10.1111/imb.12886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Accepted: 11/29/2023] [Indexed: 05/08/2024]
Abstract
Paired box (Pax) genes are highly conserved throughout evolution, and the Pax protein is an important transcription factor of embryonic development. The Pax gene Bmgsb is expressed in the silk glands of silkworm, but its biological functions remain unclear. This study aimed to investigate the expression pattern of Bmgsb in the silk gland and explore its functions using RNA interference (RNAi). Here, we identified eight Pax genes in Bombyx mori. Phylogenetic analysis showed that the B. mori Pax genes were highly homologous to the Pax genes in other insects and highly evolutionarily conserved. The tissue expression profile showed that Bmgsb was expressed in the anterior silk gland and anterior part of the middle silk gland (AMSG). RNAi of Bmgsb resulted in defective development of the AMSG, and the larvae were mostly unable to cocoon in the wandering stage. RNA-seq analysis showed that the fibroin genes fib-l, fib-h and p25, cellular heat shock response-related genes and phenol oxidase genes were considerably upregulated upon Bmgsb knockdown. Furthermore, quantitative reverse transcription-PCR results showed that the fibroin genes and ubiquitin proteolytic enzyme-related genes were significantly upregulated in the AMSG after Bmgsb knockdown. This study provides a foundation for future research on the biological functions of B. mori Pax genes. In addition, it demonstrates the important roles of Bmgsb in the transcriptional regulation of fibroin genes and silk gland development.
Collapse
Affiliation(s)
- Hongguo Yang
- State Key Laboratory of Resource Insects, Southwest University, Chongqing, China
| | - Yongping Xu
- State Key Laboratory of Resource Insects, Southwest University, Chongqing, China
| | - Yutong Yuan
- State Key Laboratory of Resource Insects, Southwest University, Chongqing, China
| | - Xuebing Liu
- State Key Laboratory of Resource Insects, Southwest University, Chongqing, China
| | - Jikailang Zhang
- State Key Laboratory of Resource Insects, Southwest University, Chongqing, China
| | - Jiaojiao Li
- State Key Laboratory of Resource Insects, Southwest University, Chongqing, China
| | - Ran Zhang
- State Key Laboratory of Resource Insects, Southwest University, Chongqing, China
| | - Jun Cao
- State Key Laboratory of Resource Insects, Southwest University, Chongqing, China
| | - Tingcai Cheng
- State Key Laboratory of Resource Insects, Southwest University, Chongqing, China
- Cancer Center, Medical Research Institute, Southwest University, Chongqing, China
- Jinfeng Laboratory, Chongqing, China
| | - Chun Liu
- State Key Laboratory of Resource Insects, Southwest University, Chongqing, China
- Cancer Center, Medical Research Institute, Southwest University, Chongqing, China
- Jinfeng Laboratory, Chongqing, China
| |
Collapse
|
2
|
Barton-Owen TB, Ferrier DEK, Somorjai IML. Pax3/7 duplicated and diverged independently in amphioxus, the basal chordate lineage. Sci Rep 2018; 8:9414. [PMID: 29925900 PMCID: PMC6010424 DOI: 10.1038/s41598-018-27700-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Accepted: 06/06/2018] [Indexed: 01/06/2023] Open
Abstract
The Pax3/7 transcription factor family is integral to developmental gene networks contributing to important innovations in vertebrate evolution, including the neural crest. The basal chordate lineage of amphioxus is ideally placed to understand the dynamics of the gene regulatory network evolution that produced these novelties. We report here the discovery that the cephalochordate lineage possesses two Pax3/7 genes, Pax3/7a and Pax3/7b. The tandem duplication is ancestral to all extant amphioxus, occurring in both Asymmetron and Branchiostoma, but originated after the split from the lineage leading to vertebrates. The two paralogues are differentially expressed during embryonic development, particularly in neural and somitic tissues, suggesting distinct regulation. Our results have implications for the study of amphioxus regeneration, neural plate and crest evolution, and differential tandem paralogue evolution.
Collapse
Affiliation(s)
- Thomas B Barton-Owen
- University of St Andrews, Gatty Marine Laboratory, Scottish Oceans Institute, East Sands, St Andrews, Fife, KY16 8LB, UK.,University of St Andrews, Biomedical Sciences Research Complex, North Haugh, St Andrews, Fife, KY16 9ST, UK
| | - David E K Ferrier
- University of St Andrews, Gatty Marine Laboratory, Scottish Oceans Institute, East Sands, St Andrews, Fife, KY16 8LB, UK
| | - Ildikó M L Somorjai
- University of St Andrews, Gatty Marine Laboratory, Scottish Oceans Institute, East Sands, St Andrews, Fife, KY16 8LB, UK. .,University of St Andrews, Biomedical Sciences Research Complex, North Haugh, St Andrews, Fife, KY16 9ST, UK.
| |
Collapse
|
3
|
Liu X, Li G, Liu X, Wang YQ. The role of the Pax1/9 gene in the early development of amphioxus pharyngeal gill slits. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2015; 324:30-40. [PMID: 25504927 DOI: 10.1002/jez.b.22596] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The pharynx is a major characteristic of chordates. Compared with vertebrates, amphioxus has an advantage for the study of pharynx development, as embryos lack neural crest, and the pharynx is mainly derived from endoderm cells. The Pax1/9 subfamily genes have essential roles in vertebrate pharyngeal patterning, but it is not known if the Pax1/9 gene has similar functions in amphioxus pharynx development. To answer this question, we examined the Pax1/9 gene expression pattern in amphioxus embryos at different developmental stages, and observed morphological changes following Pax1/9 knockdown. RT-qPCR analysis indicated that Pax1/9 expression was initiated during early neurula stage and rapidly peaked during mid-neurula stage. Furthermore, in situ hybridization analysis showed that Pax1/9 transcripts were localized exclusively in the most endodermal region of the developing pharynx in early neurula stage embryos; however, Pax1/9 expression was strikingly down-regulated in the region where gill slits would form from the fusion of endoderm and ectoderm in subsequent developmental stages and was maintained in the border regions between adjacent gill slits. Knockdown of Pax1/9 function using both morpholino and siRNA approaches led to embryonic defects in the first three gill slits, and fusion of the first two gill slits. Moreover, the expression levels of the pharyngeal marker genes Six1/2 and Tbx1/10 were reduced in Pax1/9 knockdown embryos. From these observations, we concluded that the Pax1/9 gene has an important role in the initial differentiation of amphioxus pharyngeal endoderm and in the formation of gill slits, most likely via modulation of Six1/2 and Tbx1/10 expression.
Collapse
Affiliation(s)
- Xin Liu
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian, China
| | | | | | | |
Collapse
|
4
|
Paixão-Côrtes VR, Salzano FM, Bortolini MC. Evolutionary history of chordate PAX genes: dynamics of change in a complex gene family. PLoS One 2013; 8:e73560. [PMID: 24023886 PMCID: PMC3759438 DOI: 10.1371/journal.pone.0073560] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Accepted: 07/23/2013] [Indexed: 12/22/2022] Open
Abstract
Paired box (PAX) genes are transcription factors that play important roles in embryonic development. Although the PAX gene family occurs in animals only, it is widely distributed. Among the vertebrates, its 9 genes appear to be the product of complete duplication of an original set of 4 genes, followed by an additional partial duplication. Although some studies of PAX genes have been conducted, no comprehensive survey of these genes across the entire taxonomic unit has yet been attempted. In this study, we conducted a detailed comparison of PAX sequences from 188 chordates, which revealed restricted variation. The absence of PAX4 and PAX8 among some species of reptiles and birds was notable; however, all 9 genes were present in all 74 mammalian genomes investigated. A search for signatures of selection indicated that all genes are subject to purifying selection, with a possible constraint relaxation in PAX4, PAX7, and PAX8. This result indicates asymmetric evolution of PAX family genes, which can be associated with the emergence of adaptive novelties in the chordate evolutionary trajectory.
Collapse
Affiliation(s)
- Vanessa Rodrigues Paixão-Côrtes
- Departamento de Genética and Programa de Pós-Graduação em Genética e Biologia Molecular, Instituto de Biociências, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
| | | | | |
Collapse
|
5
|
Alternative splicing: a potential source of functional innovation in the eukaryotic genome. INTERNATIONAL JOURNAL OF EVOLUTIONARY BIOLOGY 2012; 2012:596274. [PMID: 22811948 PMCID: PMC3395134 DOI: 10.1155/2012/596274] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/11/2012] [Revised: 04/19/2012] [Accepted: 05/07/2012] [Indexed: 01/21/2023]
Abstract
Alternative splicing (AS) is a common posttranscriptional process in eukaryotic organisms, by which multiple distinct functional transcripts are produced from a single gene. The release of the human genome draft revealed a much smaller number of genes than anticipated. Because of its potential role in expanding protein diversity, interest in alternative splicing has been increasing over the last decade. Although recent studies have shown that 94% human multiexon genes undergo AS, evolution of AS and thus its potential role in functional innovation in eukaryotic genomes remain largely unexplored. Here we review available evidence regarding the evolution of AS prevalence and functional role. In addition we stress the need to correct for the strong effect of transcript coverage in AS detection and set out a strategy to ultimately elucidate the extent of the role of AS in functional innovation on a genomic scale.
Collapse
|