Adding to the recombineering toolbox: interrogating internal transcriptional complexity in Caenorhabditis elegans operons via recombineered fosmid-based reporters
type: CreativeWork
description: Operons are common in prokaryotic genomes but, except for Nematoda, are uncommon in eukaryotes. Nematoda operons comprise gene clusters, containing between two to eight genes, with short, approximately. 100 bp, intergenic regions. Operons are common in C. elegans with an estimated 17% of genes clustered in operons. The significance of Nematoda operons is unclear although evidence suggests they may have arisen during genome evolution and compaction - the so-called "easy come, slow go" theory. Conventionally a discrete nascent transcript, transcribed from a major promoter upstream of the first gene in the operon, undergoes frans-splicing and 5’ addition of one of two splice-leader sequences followed by ds-splicing of the resulting pre-mRNAs to form mature, discrete mRNAs. However evidence suggests operon gene transcription is likely to be more complex. For example, microarray data indicated that correlated operon gene expression is weaker with increasing intergenic distance suggesting expression is influenced by sequence elements located internally within the operon structure. Further evidence, derived from comparison of expression data generated with fluorescent protein (FP) transcriptional reporters driven by either the upstream "operon promoter" alone or by such potential intergenic "internal promoter" sequences, generated different expression patterns in different tissues. Such data indicated the presence of internal regulatory elements within a subset of operons which were subsequently termed "hybrid operons". An alternative method to further dissect the presence of such internal regulatory elements would be to utilize translational style reporters built directly from genomic clones in which an entire operon structure is contained within the insert sequence. Tagging each operon gene with a different FP would permit operon gene expression analysis within the genomic context of that operon. To facilitate construction of fosmid-based translational reporters via seam…
abstract: Operons are common in prokaryotic genomes but, except for Nematoda, are uncommon in eukaryotes. Nematoda operons comprise gene clusters, containing between two to eight genes, with short, approximately. 100 bp, intergenic regions. Operons are common in C. elegans with an estimated 17% of genes clustered in operons. The significance of Nematoda operons is unclear although evidence suggests they may have arisen during genome evolution and compaction - the so-called "easy come, slow go" theory. Conventionally a discrete nascent transcript, transcribed from a major promoter upstream of the first gene in the operon, undergoes frans-splicing and 5’ addition of one of two splice-leader sequences followed by ds-splicing of the resulting pre-mRNAs to form mature, discrete mRNAs. However evidence suggests operon gene transcription is likely to be more complex. For example, microarray data indicated that correlated operon gene expression is weaker with increasing intergenic distance suggesting expression is influenced by sequence elements located internally within the operon structure. Further evidence, derived from comparison of expression data generated with fluorescent protein (FP) transcriptional reporters driven by either the upstream "operon promoter" alone or by such potential intergenic "internal promoter" sequences, generated different expression patterns in different tissues. Such data indicated the presence of internal regulatory elements within a subset of operons which were subsequently termed "hybrid operons". An alternative method to further dissect the presence of such internal regulatory elements would be to utilize translational style reporters built directly from genomic clones in which an entire operon structure is contained within the insert sequence. Tagging each operon gene with a different FP would permit operon gene expression analysis within the genomic context of that operon. To facilitate construction of fosmid-based translational reporters via seam…
author: Hirani, Nisha
language: eng
date published: 2013-2-8
date modified: 2026-07-24T02:44:37Z
provider: King's College London
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: King's College London