RRC ID 52712
Author Ochi H, Suzuki N, Kawaguchi A, Ogino H.
Title Asymmetrically reduced expression of hand1 homeologs involving a single nucleotide substitution in a cis-regulatory element.
Journal Dev Biol
Abstract During vertebrate evolution, whole genome duplications resulted in a number of duplicated genes, some of which eventually changed their expression patterns and/or levels via alteration of cis-regulatory sequences. However, the initial process involved in such cis-regulatory changes remains unclear. Therefore, we investigated this process by analyzing the duplicated hand1 genes of Xenopus laevis (hand1.L and hand1.S), which were generated by allotetraploidization 17-18 million years ago, and compared these with their single ortholog in the ancestral-type diploid species X. tropicalis. A dN/dS analysis indicated that hand1.L and hand1.S are still under purifying selection, and thus, their products appear to retain ancestral functional properties. RNA-seq and in situ hybridization analyses revealed that hand1.L and hand1.S have similar expression patterns to each other and to X. tropicalis hand1, but the hand1.S expression level was much lower than the hand1.L expression level in the primordial heart. A comparative sequence analysis, luciferase reporter analysis, ChIP-PCR analysis, and transgenic reporter analysis showed that a single nucleotide substitution in the hand1.S promoter was responsible for the reduced expression in the heart. These findings demonstrated that a small change in the promoter sequence can trigger diversification of duplicated gene expression prior to diversification of their encoded protein functions in a young duplicated genome.
Volume 425(2)
Pages 152-160
Published 2017-5-15
DOI 10.1016/j.ydbio.2017.03.021
PII S0012-1606(16)30441-9
PMID 28359808
MeSH Amino Acid Sequence Animals Animals, Genetically Modified Base Sequence Basic Helix-Loop-Helix Transcription Factors / chemistry Basic Helix-Loop-Helix Transcription Factors / genetics* Conserved Sequence / genetics Embryo, Nonmammalian / metabolism Enhancer Elements, Genetic / genetics Gene Expression Regulation, Developmental* Genes, Reporter Humans In Situ Hybridization Polymorphism, Single Nucleotide / genetics* Promoter Regions, Genetic Regulatory Sequences, Nucleic Acid / genetics* Sequence Analysis, RNA Sequence Homology, Nucleic Acid* Synteny / genetics Xenopus / embryology Xenopus / genetics*
IF 2.936
Times Cited 1
Xenopus tropicalis Xenopus tropicalis