Transcript analysis of GH3-like gene family, with special emphasis on GH3-20 in Arabidopsis
Date Issued
2005
Date
2005
Author(s)
Chang, Hao-Chao
DOI
zh-TW
Abstract
FIN219 is an extragenic suppressor of cop1-6 and involved in phytochrome A-mediated far-red light signal transduction. It encodes a 575 amino-acid protein that belongs to the GH3-like gene family in Arabidopsis. BLAST search result indicated that there are 20 GH3-like genes present in the Arabidopsis genome. However, their function remains elusive. To further understand weather the members are all involved in light signal transductions and regulate various aspects of Arabidopsis development, several light signaling mutants and T-DNA insertion lines are utilized for the analysis of their gene expression.
Nine GH3-like genes, including GH3-1, GH3-2, GH3-3, GH3-4, GH3-5, GH3-6, GH3-9, GH3-18, and GH3-20, were chosed for studies of the functional roles in light signaling. Motif-searching analysis indicated that each of the primary sequences predicted from these nine genes contained 1-2 coiled-coil domains that were believed to be responsible for protein-protein interactions. As well, it was found that there are several light-regulated cis-elements such as GATA box and IBOX present in the promoters of these GH3-like genes. Consistently, the results of RT-PCR by using gene specific primers have revealed that the expression of the GH3-like genes was actually affected by different photoreceptors and some light signaling components. Furthermore, T-DNA insertion lines for some of these GH3-like members exhibited a long hypocotyl phenotype under FR, Blue (B), and red (R) light conditions, and this phenotype was light fluence-dependent. Taken together, these data indicate that the GH3-like gene family in Arabidopsis was indeed involved in light signaling pathway and may play an important role in FR, R and B-mediated inhibition of the hypocotyl elongation.
In addition, we also overexpressed or antisensed the GH3-20 gene encoding 190 amino acids in wild type Arabidopsis and various light responsive mutants to investigate the effect on plant development. Preliminary results indicated that the transgenic seedlings overexpressing the GH3-20 gene only in wild-type background rather than in other mutants exhibited a long hypocotyl phenotype under FR. However, the transgenic seedlings inhibiting the GH3-20 gene expression did not show any obvious phenotype under FR, which suggests that GH3-20 may have a redundant function with other members of the GH3-like gene family in Arabidopsis. That transgenic seedlings overexpressing the GH3-20 gene in phyA, phyB, fin219, cry1 and cry2 mutants did not show obvious phenotypes is a good implication that its expression may require these proteins to function correctly in FR.
By using RT-PCR, GH3-20 displays a tissue-specific manner with high levels of the transcripts in roots, but is not detectable in other tissues, which implies that GH3-20 may have physiological functions in root development. Moreover, the transient assay of subcellular localizations of the GH3-20 by particle bombardment in onion cells showed that GH3-20 exists in both the cytosol and the nucleus without changes by light.
Nine GH3-like genes, including GH3-1, GH3-2, GH3-3, GH3-4, GH3-5, GH3-6, GH3-9, GH3-18, and GH3-20, were chosed for studies of the functional roles in light signaling. Motif-searching analysis indicated that each of the primary sequences predicted from these nine genes contained 1-2 coiled-coil domains that were believed to be responsible for protein-protein interactions. As well, it was found that there are several light-regulated cis-elements such as GATA box and IBOX present in the promoters of these GH3-like genes. Consistently, the results of RT-PCR by using gene specific primers have revealed that the expression of the GH3-like genes was actually affected by different photoreceptors and some light signaling components. Furthermore, T-DNA insertion lines for some of these GH3-like members exhibited a long hypocotyl phenotype under FR, Blue (B), and red (R) light conditions, and this phenotype was light fluence-dependent. Taken together, these data indicate that the GH3-like gene family in Arabidopsis was indeed involved in light signaling pathway and may play an important role in FR, R and B-mediated inhibition of the hypocotyl elongation.
In addition, we also overexpressed or antisensed the GH3-20 gene encoding 190 amino acids in wild type Arabidopsis and various light responsive mutants to investigate the effect on plant development. Preliminary results indicated that the transgenic seedlings overexpressing the GH3-20 gene only in wild-type background rather than in other mutants exhibited a long hypocotyl phenotype under FR. However, the transgenic seedlings inhibiting the GH3-20 gene expression did not show any obvious phenotype under FR, which suggests that GH3-20 may have a redundant function with other members of the GH3-like gene family in Arabidopsis. That transgenic seedlings overexpressing the GH3-20 gene in phyA, phyB, fin219, cry1 and cry2 mutants did not show obvious phenotypes is a good implication that its expression may require these proteins to function correctly in FR.
By using RT-PCR, GH3-20 displays a tissue-specific manner with high levels of the transcripts in roots, but is not detectable in other tissues, which implies that GH3-20 may have physiological functions in root development. Moreover, the transient assay of subcellular localizations of the GH3-20 by particle bombardment in onion cells showed that GH3-20 exists in both the cytosol and the nucleus without changes by light.
Subjects
阿拉伯芥
光訊息傳遞
光調控
基因家族
GH3-like
gene family
Arabidopsis
GH3-20
light
Type
other
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