ドロソフィラと植物における反転反復トランポゾンの一般的な進化的起源の証拠:ホボ,アクティベーター,タム3
B R Calvi1, T J Hong, S D Findley
1Department of Cellular and Developmental Biology, Harvard University, Cambridge, Massachusetts 02138-2097.
Cell
|August 9, 1991
まとめ
研究者たちはフルーツハエのHFL1遺伝子を配列化し,トウモロコシやスナップドラゴンのトランポゼに似たトランポゼを明らかにした. この発見は,植物と動物の間の潜在的な水平遺伝子転送を示唆しています.
科学分野:
- 分子生物学は分子生物学である.
- 遺伝学 遺伝学とは
- 進化生物学の進化生物学について
背景:
- ホボエレメントは,果物ハエ (Drosophila melanogaster) にある転置可能な元素です.
- HFL1は,トランポザース活性が実証されている唯一のクローンされたホボエレメントです.
- Hobo,Ac,Tam3のようなトランスポーザブル要素は,移動性遺伝子配列である.
研究 の 目的:
- D. melanogaster. の HFL1 要素の配列を決定し,分析する.
- HFL1トランスポザーゼ内の保存された領域の機能的重要性を調査する.
- 異なった王国における転置可能な元素の間の進化的関係を探求する.
主な方法:
- HFL1要素のDNAシーケンシング.
- 生物情報分析は,開いた読み取りフレームを予測し,アミノ酸配列を比較します.
- HFL1トランスポザースのC末端領域の変異分析.
主要な成果:
- HFL1配列 (2959 bp) は,2.0kBのオープン・リーディングフレーム (ORF1) を予測しています.
- ORF1は,トウモロコシのアクティベーター (Ac) とスナップドラゴンのTam3のトランスポーゼと,重要なアミノ酸類似性を示しています.
- 変異分析により,ORF1のC端末領域が保存されていて,ホボトランポザース活性に欠かせないことが確認されました.
結論:
- HFL1トランスポゼは,植物トランスポゼと保存された機能領域を共有しており,深層の進化的保存を示しています.
- 広範な配列同一性は,植物と動物の間で移植可能な元素の水平遺伝子転送の可能性を示唆しています.
- この研究は,多様なエウカリオット王国における転置の保存されたメカニズムの証拠を提供します.
関連する概念動画
Position-effect Variegation
In 1928, a German botanist Emil Heitz observed the moss nuclei with a DNA binding dye. He observed that while some chromatin regions decondense and spread out in the interphase nucleus, others do not. He termed them euchromatin and heterochromatin, respectively. He proposed that the heterochromatin regions reflect a functionally inactive state of the genome. It was later confirmed that heterochromatin is transcriptionally repressed, and euchromatin is transcriptionally active chromatin.
Overview of Transposition and Recombination
Transposons make up a significant part of genomes of various organisms. Therefore, it is believed that transposition played a major evolutionary role in speciation by changing genome sizes and modifying gene expression patterns. For example, in bacteria, transposition can lead to conferring antibiotic resistance. Movement of transposable elements within the genetic pool of pathogenic bacteria can aid in transfer of antibiotic-resistant genetic elements. In eukaryotes, transposons can carry out...
DNA-only Transposons
DNA-only transposons are called autonomous transposons since they code for the enzyme transposase that is required for the transposition mechanism. Insertion of transposons can alter gene functions in multiple ways. They can mutate the gene, alter gene expression by introducing a novel promoter or insulator sequence, introduce new splice sites, and change the mRNA transcripts produced, or remodel chromatin structure.
The donor site from where the transposon is excised is either degraded or...
The donor site from where the transposon is excised is either degraded or...
LTR Retrotransposons
LTR retrotransposons are class I transposable elements with long terminal repeats flanking an internal coding region. These elements are less abundant in mammals compared to other class I transposable elements. About 8 percent of human genomic DNA comprises LTR retrotransposons. Some of the common examples of LTR retrotransposons are Ty elements in yeast and Copia elements in Drosophila.
The internal coding region of LTR retrotransposons and their mechanism of transposition closely resembles a...
The internal coding region of LTR retrotransposons and their mechanism of transposition closely resembles a...
Cis-regulatory Sequences
Cis-regulatory sequences are short fragments of non-coding DNA that are present on the same chromosomes as the genes that they regulate. These fragments serve as binding sites for transcriptional regulators, proteins that are responsible for controlling gene transcription and differential gene expression across cell types in eukaryotes. Cis-regulatory sequences can be close to the gene of interest or thousands of bases away in the DNA sequence; however, those sequences that are further away are...
Exon Recombination
The evolution of new genes is critical for speciation. Exon recombination, also known as exon shuffling or domain shuffling, is an important means of new gene formation. It is observed across vertebrates, invertebrates, and in some plants such as potatoes and sunflowers. During exon recombination, exons from the same or different genes recombine and produce new exon-intron combinations, which might evolve into new genes.
Exon shuffling follows “splice frame rules.” Each exon has three reading...
Exon shuffling follows “splice frame rules.” Each exon has three reading...


