achaete-scute feminizing activities and Drosophila sex determination

Development ◽  
1993 ◽  
Vol 117 (2) ◽  
pp. 737-749 ◽  
Author(s):  
S.M. Parkhurst ◽  
H.D. Lipshitz ◽  
D. Ish-Horowicz
Keyword(s):  
Gene Expression ◽  
Protein Expression ◽  
Sex Determination ◽  
Detailed Examination ◽  
Bhlh Gene ◽  
Basic Helix Loop Helix ◽  
Helix Loop Helix ◽  
Bhlh Genes ◽  
Sex Lethal

Sex determination in Drosophila depends on X-linked ‘numerator’ genes activating early Sex-lethal (Sxl) transcription in females. One numerator gene, sisterless-b (sis-b), corresponds to the achaete-scute (AS-C) T4 basic-helix-loop-helix (bHLH) gene. Two other closely related AS-C bHLH genes, T3 and T5, appear not to function as numerator elements. We analyzed endogenous AS-C expression and show that T4 is the major AS-C numerator gene because it is expressed earlier and more strongly than are T3 and T5. Only T4 expression is detectable during the early syncytial stages when Sxl state is being determined. Nevertheless, the effects of ectopic AS-C gene expression show that T3 and T5 proteins display weak but significant feminizing activities, enhancing male-lethality, and rescuing the female-lethality of sis mutations. Detailed examination of Sxl expression in rescued embryos suggests that female cells may be viable in the absence of detectable Sxl protein expression.

scholarly journals Basic Helix-Loop-Helix Transcription Factors Cooperate To Specify a Cortical Projection Neuron Identity

2007 ◽  
Vol 28 (5) ◽  
pp. 1456-1469 ◽  
Author(s):  
Pierre Mattar ◽  
Lisa Marie Langevin ◽  
Kathryn Markham ◽  
Natalia Klenin ◽  
Salma Shivji ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transcription Factors ◽  
Projection Neuron ◽  
Luciferase Assay ◽  
Bhlh Gene ◽  
Cortical Projection ◽  
Basic Helix Loop Helix ◽  
Helix Loop Helix ◽  
Bhlh Genes ◽  
Cortical Projection Neuron

ABSTRACT Several transcription factors are essential determinants of a cortical projection neuron identity, but their mode of action (instructive versus permissive) and downstream genetic cascades remain poorly defined. Here, we demonstrate that the proneural basic helix-loop-helix (bHLH) gene Ngn2 instructs a partial cortical identity when misexpressed in ventral telencephalic progenitors, inducing ectopic marker expression in a defined temporal sequence, including early (24 h; Nscl2), intermediate (48 h; BhlhB5), and late (72 h; NeuroD, NeuroD2, Math2, and Tbr1) target genes. Strikingly, cortical gene expression was much more rapidly induced by Ngn2 in the dorsal telencephalon (within 12 to 24 h). We identify the bHLH gene Math3 as a dorsally restricted Ngn2 transcriptional target and cofactor, which synergizes with Ngn2 to accelerate target gene transcription in the cortex. Using a novel in vivo luciferase assay, we show that Ngn2 generates only ∼60% of the transcriptional drive in ventral versus dorsal telencephalic domains, an activity that is augmented by Math3, providing a mechanistic basis for regional differences in Ngn2 function. Cortical bHLH genes thus cooperate to control transcriptional strength, thereby temporally coordinating downstream gene expression.

Math5 encodes a murine basic helix-loop-helix transcription factor expressed during early stages of retinal neurogenesis

Development ◽  
1998 ◽  
Vol 125 (23) ◽  
pp. 4821-4833 ◽  
Author(s):  
N.L. Brown ◽  
S. Kanekar ◽  
M.L. Vetter ◽  
P.K. Tucker ◽  
D.L. Gemza ◽  
...  
Keyword(s):  
Bipolar Cells ◽  
Dependent Manner ◽  
Bhlh Gene ◽  
Basic Helix Loop Helix ◽  
Helix Loop Helix ◽  
Frog Retina ◽  
Similar Dose ◽  
Bhlh Genes ◽  
Hes1 Expression ◽  
Retinal Neurogenesis

We have identified Math5, a mouse basic helix-loop-helix (bHLH) gene that is closely related to Drosophila atonal and Xenopus Xath5 and is largely restricted to the developing eye. Math5 retinal expression precedes differentiation of the first neurons and persists within progenitor cells until after birth. To position Math5 in a hierarchy of retinal development, we compared Math5 and Hes1 expression in wild-type and Pax6-deficient (Sey) embryos. Math5 expression is downregulated in Sey/+ eyes and abolished in Sey/Sey eye rudiments, whereas the bHLH gene Hes1 is upregulated in a similar dose-dependent manner. These results link Pax6 to the process of retinal neurogenesis and provide the first molecular correlate for the dosage-sensitivity of the Pax6 phenotype. During retinogenesis, Math5 is expressed significantly before NeuroD, Ngn2 or Mash1. To test whether these bHLH genes influence the fates of distinct classes of retinal neurons, we ectopically expressed Math5 and Mash1 in Xenopus retinal progenitors. Unexpectedly, lipofection of either mouse gene into the frog retina caused an increase in differentiated bipolar cells. Directed expression of Math5, but not Xath5, in Xenopus blastomeres produced an expanded retinal phenotype. We propose that Math5 acts as a proneural gene, but has properties different from its most closely related vertebrate family member, Xath5.

scholarly journals Characterization of the basic helix–loop–helix gene family and its tissue-differential expression in response to salt stress in poplar

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4502 ◽  
Author(s):  
Kai Zhao ◽  
Shuxuan Li ◽  
Wenjing Yao ◽  
Boru Zhou ◽  
Renhua Li ◽  
...  
Keyword(s):  
Gene Expression ◽  
Salt Stress ◽  
Gene Family ◽  
Gene Expression Profiling ◽  
Differential Expression ◽  
Expression Profiling ◽  
Bhlh Transcription Factor ◽  
Basic Helix Loop Helix ◽  
Helix Loop Helix ◽  
Bhlh Genes

The basic helix–loop–helix (bHLH) transcription factor gene family is one of the largest gene families and extensively involved in plant growth, development, and stress responses. However, limited studies are available on the gene family in poplar. In this study, we focused on 202 bHLH genes, exploring their DNA and protein sequences and physicochemical properties. According to their protein sequence similarities, we classified the genes into 25 groups with specific motif structures. In order to explore their expressions, we performed gene expression profiling using RNA-Seq and identified 19 genes that display tissue-differential expression patterns without treatment. Furthermore, we also performed gene expression profiling under salt stress. We found 74 differentially expressed genes (DEGs), which are responsive to the treatment. A total of 18 of the 19 genes correspond well to the DEGs. We validated the results using reverse transcription quantitative real-time PCR. This study lays the foundation for future studies on gene cloning, transgenes, and biological mechanisms.

scholarly journals A Classification of Basic Helix-Loop-Helix Transcription Factors of Soybean

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Karen A. Hudson ◽  
Matthew E. Hudson
Keyword(s):  
Transcription Factors ◽  
Genome Sequence ◽  
Search Algorithm ◽  
Soybean Genome ◽  
Binding Potential ◽  
Future Research ◽  
Basic Helix Loop Helix ◽  
Helix Loop Helix ◽  
Bhlh Genes ◽  
Wide Range

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.

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

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.

Wingless blocks bristle formation and morphogenetic furrow progression in the eye through repression of Daughterless

Development ◽  
2002 ◽  
Vol 129 (14) ◽  
pp. 3393-3402 ◽  
Author(s):  
Kenneth M. Cadigan ◽  
Austin D. Jou ◽  
Roel Nusse
Keyword(s):  
Gene Expression ◽  
Ectopic Expression ◽  
Dominant Negative ◽  
Proneural Gene ◽  
Morphogenetic Furrow ◽  
Heterologous Promoter ◽  
Basic Helix Loop Helix ◽  
Helix Loop Helix ◽  
Dominant Negative Form ◽  
Negative Form

In the developing eye, wingless activity represses proneural gene expression (and thus interommatidial bristle formation) and positions the morphogenetic furrow by blocking its initiation in the dorsal and ventral regions of the presumptive eye. We provide evidence that wingless mediates both effects, at least in part, through repression of the basic helix-loop-helix protein Daughterless. daughterless is required for high proneural gene expression and furrow progression. Ectopic expression of wingless blocks Daughterless expression in the proneural clusters. This repression, and that of furrow progression, can be mimicked by an activated form of armadillo and blocked by a dominant negative form of pangolin/TCF. Placing daughterless under the control of a heterologous promoter blocks the ability of ectopic wingless to inhibit bristle formation and furrow progression. hedgehog and decapentapleigic could not rescue the wingless furrow progression block, indicating that wingless acts downstream of these genes. In contrast, Atonal and Scute, which are thought to heterodimerize with Daughterless to promote furrow progression and bristle formation, respectively, can block ectopic wingless action. These results are summarized in a model where daughterless is a major, but probably not the only, target of wingless action in the eye.

The Notch ligand, X-Delta-2, mediates segmentation of the paraxial mesoderm in Xenopus embryos

Development ◽  
1997 ◽  
Vol 124 (6) ◽  
pp. 1169-1178 ◽  
Author(s):  
W.C. Jen ◽  
D. Wettstein ◽  
D. Turner ◽  
A. Chitnis ◽  
C. Kintner
Keyword(s):  
Paraxial Mesoderm ◽  
Bhlh Gene ◽  
Presomitic Mesoderm ◽  
Notch 1 ◽  
Notch Ligand ◽  
Basic Helix Loop Helix ◽  
Helix Loop Helix ◽  
Vertebrate Embryo ◽  
Somite Formation ◽  
Segmental Expression

Segmentation of the vertebrate embryo begins when the paraxial mesoderm is subdivided into somites, through a process that remains poorly understood. To study this process, we have characterized X-Delta-2, which encodes the second Xenopus homolog of Drosophila Delta. Strikingly, X-Delta-2 is expressed within the presomitic mesoderm in a set of stripes that corresponds to prospective somitic boundaries, suggesting that Notch signaling within this region establishes a segmental prepattern prior to somitogenesis. To test this idea, we introduced antimorphic forms of X-Delta-2 and Xenopus Suppressor of Hairless (X-Su(H)) into embryos, and assayed the effects of these antimorphs on somite formation. In embryos expressing these antimorphs, the paraxial mesoderm differentiated normally into somitic tissue, but failed to segment properly. Both antimorphs also disrupted the segmental expression of X-Delta-2 and Hairy2A, a basic helix-loop-helix (bHLH) gene, within the presomitic mesoderm. These observations suggest that X-Delta-2, via X-Notch-1, plays a role in segmentation, by mediating cell-cell interactions that underlie the formation of a segmental prepattern prior to somitogenesis.

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

2019 ◽  
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.

A genome-wide identification and classification of basic helix-loop-helix genes in the jewel wasp, Nasonia vitripennis (Hymenoptera: Pteromalidae)

Genome ◽  
2014 ◽  
Vol 57 (10) ◽  
pp. 525-536 ◽  
Author(s):  
Xiao-Ting Liu ◽  
Yong Wang ◽  
Xu-Hua Wang ◽  
Xia-Fang Tao ◽  
Qin Yao ◽  
...  
Keyword(s):  
Heart Development ◽  
Family Members ◽  
Insect Species ◽  
Structural Domain ◽  
Nasonia Vitripennis ◽  
Basic Helix Loop Helix ◽  
Helix Loop Helix ◽  
A Genome ◽  
Bhlh Genes ◽  
Bhlh Proteins

Basic helix-loop-helix (bHLH) proteins are highly conserved DNA-binding transcription factors of a large superfamily. Animal bHLH proteins play important regulatory roles in various developmental processes such as neurogenesis, myogenesis, heart development, and hematopoiesis. The jewel wasp (Nasonia vitripennis) is a good model organism of hymenoptera insects for studies of developmental and evolutionary genetics. In this study, we identified 48 bHLH genes in the genome of N. vitripennis. According to phylogenetic analysis, based on N. vitripennis bHLH (NvbHLH) motif sequences and structural domain distribution in their full-length protein sequences, the identified NvbHLH genes were classified into 36 bHLH families with 19, 12, 9, 1, 6, and 1 member(s) in groups A, B, C, D, E, and F, respectively. Our classification to the identified NvbHLH family members confirms GenBank annotations for 21 of the 48 NvbHLH proteins and provides useful information for further characterization and annotation of the remaining 27 NvbHLH proteins. Compared to other insect species, N. vitripennis has the lowest number of bHLH family members. No NvbHLH members have been found in the families Net, MyoRa, and PTFa, while all other insect species have at least one member in each of the families. These data constitute a solid basis for further investigations into the functions of bHLH proteins in developmental regulation of N. vitripennis.

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