Exploration of non-canonical expression of developmental genes in the asexual viviparous pea aphid using fluorescence approaches
Date Issued
2014
Date
2014
Author(s)
Chung, Chen-yo
Abstract
The pea aphid Acyrthosiphon pisum is a genomic model insect and a unique model for polyphenism due to its developmental plasticity in response to environmental cues. To uncover the relation of embryonic development and gene regulations, reliable expression protocols and functional tools are required. Whole-mount in situ hybridization (WISH) we previously reported can be used to monitor gene expressions during embryogenesis, however chromogenic signals are defective in double detection of genes and construction of three-dimensional image. I therefore developed a fluorescent in situ hybridization (FISH) protocol to overcome these defects. By means of different advantages of four FISH methods, I successfully detected gene expressions in somatic and extraembryonic tissues. The combination of FISH methods also allowed the double detection of genes in somatic cells, germ cells, or both in one preparation. This FISH protocol further aids me in revealing the expression of developmental genes. In our previous findings, mRNA expression of A. pisum hunchback (Aphb), a Drosophila homolog of hunchback, was found in the segments and central nervous system of mid/late stages apart from the anterior pole of early stages, implicating its conserved roles among arthropods and lower organisms. Here I discovered a novel expression pattern of Aphb in germ cells of the pea aphid. Germline expression of Aphb initiates while primordial germ cells formed, and maintains throughout developmental stages. In late embryos, Aphb is also expressed in maturing germaria as well as the protruding oocytes. These findings implicate that the homolog of hb in aphids replaces the role of bicoid in anterior determination and, moreover, has the roles in formation of germ cells. To reveal whether the complex of Nanos (Nos) and Pumilio (Pum) is required to repress the translation of anterior-localized Aphb in the posterior, I analyzed the structure of A. pisum Pum (ApPum) protein and the expression patterns of Appum mRNA. The highly conserved protein structure indicates the ApPum can repress the translation of Aphb, though the asymmetric expression of Appum mRNA, like Drosophila pum, was not found. Together with the known expression patterns of Aphb, Appum, and A. pisum Nos (ApNos), it appears that posterior determination of the pea aphid relies on the ApNos/ApPum complex and the anterior is determined by Aphb.
Subjects
豌豆蚜
前後體軸
全體螢光原位雜合
生殖細胞
hunchback
pumilio
SDGs
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-103-D96632003-1.pdf
Size
23.54 KB
Format
Adobe PDF
Checksum
(MD5):4a3b256e0d33d88d11314d5dd3fd0867