Molecular characterization of the basic helix-loop-helix (bHLH) genes that are differentially expressed and induced by iron deficiency in Populus

The complete genome sequence of soybean allows an unprecedented opportunity for the discovery of the genes controlling important traits. In particular, the potential functions of regulatory genes are a priority for analysis. The basic helix-loop-helix (bHLH) family of transcription factors is known to be involved in controlling a wide range of systems critical for crop adaptation and quality, including photosynthesis, light signalling, pigment biosynthesis, and seed pod development. Using a hidden Markov model search algorithm, 319 genes with basic helix-loop-helix transcription factor domains were identified within the soybean genome sequence. These were classified with respect to their predicted DNA binding potential, intron/exon structure, and the phylogeny of the bHLH domain. Evidence is presented that the vast majority (281) of these 319 soybean bHLH genes are expressed at the mRNA level. Of these soybean bHLH genes, 67% were found to exist in two or more homeologous copies. This dataset provides a framework for future studies on bHLH gene function in soybean. The challenge for future research remains to define functions for the bHLH factors encoded in the soybean genome, which may allow greater flexibility for genetic selection of growth and environmental adaptation in this widely grown crop.

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A novel basic helix-loop-helix protein is expressed in muscle attachment sites of the Drosophila epidermis

Molecular and Cellular Biology ◽

10.1128/mcb.14.6.4145-4154.1994 ◽

1994 ◽

Vol 14 (6) ◽

pp. 4145-4154

Author(s):

P Armand ◽

A C Knapp ◽

A J Hirsch ◽

E F Wieschaus ◽

M D Cole

Keyword(s):

Distinct Pattern ◽

Bhlh Protein ◽

Muscle Attachment ◽

Muscle Creatine Kinase ◽

Basic Helix Loop Helix ◽

Helix Loop Helix ◽

Attachment Sites ◽

Bhlh Genes ◽

Somatic Muscles ◽

Muscle Attachment Sites

We have found that a novel basic helix-loop-helix (bHLH) protein is expressed almost exclusively in the epidermal attachments sites for the somatic muscles of Drosophila melanogaster. A Drosophila cDNA library was screened with radioactively labeled E12 protein, which can dimerize with many HLH proteins. One clone that emerged from this screen encoded a previously unknown protein of 360 amino acids, named delilah, that contains both basic and HLH domains, similar to a group of cellular transcription factors implicated in cell type determination. Delilah protein formed heterodimers with E12 that bind to the muscle creatine kinase promoter. In situ hybridization with the delilah cDNA localized the expression of the gene to a subset of cells in the epidermis which form a distinct pattern involving both the segmental boundaries and intrasegmental clusters. This pattern was coincident with the known sites of attachment of the somatic muscles to tendon cells in the epidermis. delilah expression persists in snail mutant embryos which lack mesoderm, indicating that expression of the gene was not induced by attachment of the underlying muscles. The similarity of this gene to other bHLH genes suggests that it plays an important role in the differentiation of epidermal cells into muscle attachment sites.

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Isolation and characterization of R2R3-MYB and basic helix–loop–helix (bHLH) transcription factors involved in anthocyanin biosynthesis in tulip tepals

Acta Physiologiae Plantarum ◽

10.1007/s11738-020-3026-3 ◽

2020 ◽

Vol 42 (3) ◽

Author(s):

Yuan Yuan ◽

Yimin Shi ◽

Dongqin Tang

Keyword(s):

Transcription Factors ◽

Anthocyanin Biosynthesis ◽

Basic Helix Loop Helix ◽

Helix Loop Helix ◽

Isolation And Characterization ◽

R2r3 Myb ◽

Bhlh Transcription Factors

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Overexpression of PtrbHLH, a basic helix-loop-helix transcription factor from Poncirus trifoliata, confers enhanced cold tolerance in pummelo (Citrus grandis) by modulation of H2O2 level via regulating a CAT gene

Tree Physiology ◽

10.1093/treephys/tpz081 ◽

2019 ◽

Cited By ~ 3

Author(s):

Jingjing Geng ◽

Tonglu Wei ◽

Yue Wang ◽

Xiaosan Huang ◽

Ji-Hong Liu

Keyword(s):

Cold Tolerance ◽

Cold Treatment ◽

Poncirus Trifoliata ◽

Basic Helix Loop Helix ◽

Helix Loop Helix ◽

Bhlh Genes ◽

Transgenic Lines ◽

Elevated Activity ◽

H2o2 Level ◽

Cat Gene

Abstract The basic helix-loop-helix (bHLH) family of transcription factors (TFs) plays a crucial role in regulating plant response to abiotic stress by targeting a large spectrum of stress-responsive genes. However, the physiological mechanisms underlying the TF-mediated stress response are still poorly understood for most of the bHLH genes. In this study, transgenic pummelo (Citrus grandis) plants overexpressing PtrbHLH, a TF previously identified from Poncirus trifoliata, were generated via Agrobacterium-mediated transformation. In comparison with the wild-type plants, the transgenic lines exhibited significantly lower electrolyte leakage and malondialdehyde content after cold treatment, thereby resulting in a more tolerant phenotype. Meanwhile, the transgenic lines accumulated dramatically lower reactive oxygen species (ROS) levels, consistent with elevated activity and expression levels of antioxidant enzymes (genes), including catalase (CAT), peroxidase and superoxide dismutase. In addition, PtrbHLH was shown to specifically bind to and activate the promoter of PtrCAT gene. Taken together, these results demonstrated that overexpression of PtrbHLH leads to enhanced cold tolerance in transgenic pummelo, which may be due, at least partly, to modulation of ROS levels by regulating the CAT gene.

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