Biomedical subjects

Derek Lemons

Publications and source records attributed to Derek Lemons.

4 recordsLinked to original sources

PubMed2006

Genomic evolution of Hox gene clusters.

The family of Hox genes, which number 4 to 48 per genome depending on the animal, control morphologies on the main body axis of nearly all metazoans. The conventional wisdom is that Hox genes are arranged in chromosomal clusters in colinear order with their expression patterns on the body axis. However, recent evidence has shown that Hox gene clusters are fragmented, reduced, or expanded in many animals-findings that correlate with interesting morphological changes in evolution. Hox gene clusters also contain many noncoding RNAs, such as intergenic regulatory transcripts and evolutionarily conserved microRNAs, some of whose developmental functions have recently been explored.

Animals↗

PubMed2005

Dosage-dependent requirement for mouse Vezf1 in vascular system development.

Vezf1 is an early development gene that encodes a zinc finger transcription factor. In the developing embryo, Vezf1 is expressed in the yolk sac mesoderm and the endothelium of the developing vasculature and, in addition, in mesodermal and neuronal tissues. Targeted inactivation of Vezf1 in mice reveals that it acts in a closely regulated, dose-dependent fashion on the development of the blood vascular and lymphatic system. Homozygous mutant embryos display vascular remodeling defects and loss of vascular integrity leading to localized hemorrhaging. Ultrastructural analysis shows defective endothelial cell adhesion and tight junction formation in the mutant vessels. Moreover, in heterozygous embryos, haploinsufficiency is observed that is characterized by lymphatic hypervascularization associated with hemorrhaging and edema in the jugular region; a phenotype reminiscent of the human congenital lymphatic malformation syndrome cystic hygroma.

Animals↗

PubMed2005

Modulating Hox gene functions during animal body patterning.

With their power to shape animal morphology, few genes have captured the imagination of biologists as the evolutionarily conserved members of the Hox clusters have done. Recent research has provided new insight into how Hox proteins cause morphological diversity at the organismal and evolutionary levels. Furthermore, an expanding collection of sequences that are directly regulated by Hox proteins provides information on the specificity of target-gene activation, which might allow the successful prediction of novel Hox-response genes. Finally, the recent discovery of microRNA genes within the Hox gene clusters indicates yet another level of control by Hox genes in development and evolution.

Animals↗

PubMed2004

Multiplex detection of RNA expression in Drosophila embryos.

We present a fluorescence-based, multiplex in situ hybridization method that permits the simultaneous detection of five differently labeled antisense RNA probes and up to seven differ-ent transcripts in a single Drosophila embryo. We also show that it should be possible to increase the number of detected transcripts substantially with nascent transcript multiplex fluorescent in situ hybridization. These multiplex methods fill a current technological gap between high-resolution in situ hybridization with one or two fluorescently labeled probes and low-resolution but genome-wide microarray RNA profiling and should be of great utility in establishing gene networks.

Animals↗