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William McGinnis

Publications and source records attributed to William McGinnis.

14 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↗
PubMed2006

Gap peptides: A new way to control embryonic patterning?

Gap genes encode transcription factors involved in the patterning of the head-tail axis of insect embryos. In this issue of Cell, Savard et al. (2006) identify a beetle gap gene, mille-pattes, that encodes an unusual polycistronic transcript predicted to produce four conserved peptides. These results have interesting implications for the control of embryonic patterning in insects.

Animals↗
PubMed2005

An epidermal barrier wound repair pathway in Drosophila is mediated by grainy head.

We used wounded Drosophila embryos to define an evolutionarily conserved pathway for repairing the epidermal surface barrier. This pathway includes a wound response enhancer from the Ddc gene that requires grainy head (grh) function and binding sites for the Grh transcription factor. At the signaling level, tyrosine kinase and extracellular signal-regulated kinase (ERK) activities are induced in epidermal cells near wounds, and activated ERK is required for a robust wound response. The conservation of this Grh-dependent pathway suggests that the repair of insect cuticle and mammal skin is controlled by an ancient, shared control system for constructing and healing the animal body surface barrier.

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↗
PubMed2005

Evolutionarily conserved domains required for activation and repression functions of the Drosophila Hox protein Ultrabithorax.

While testing the functions of deletion mutants in the Hox protein Ultrabithorax (Ubx), we found that the embryonic repression function of Ubx on Distal-less transcription in limb primordia is highly concentration dependent. The steep sigmoidal relationship between in vivo Ubx concentration and Distal-less repression is dependent on the Ubx YPWM motif. This suggests that Ubx cooperatively assembles a multi-protein repression complex on Distal-less regulatory DNA with the YPWM motif as a key protein-protein interface in this complex. Our deletion mutants also provide evidence for a transcriptional activation domain in the N-terminal 19 amino acids of Ubx. This proposed activation domain contains a variant of the SSYF motif that is found at the N termini of many Hox proteins, and is conserved in the activation domain of another Hox protein, Sex combs reduced. These results suggest that the N-terminal region containing the SSYF motif has been conserved in many Hox proteins for its role in transcriptional activation.

Amino Acid Sequence↗
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↗
PubMed2003

Evolution of transcription factor function.

Functional assays in Drosophila melanogaster with orthologous transcription factors from other species suggest that changes in the protein-coding sequence may play a larger role in the evolution of transcription factor pathways than was previously believed. Interestingly, recent studies provide evidence that changes in transcription factor protein sequence can affect the regulation of only a subset of target genes, even in the same cells of a developing animal.

Animals↗
PubMed2002

The Drosophila Hox gene deformed sculpts head morphology via direct regulation of the apoptosis activator reaper.

Hox proteins control morphological diversity along the anterior-posterior body axis of animals, but the cellular processes they directly regulate are poorly understood. We show that during early Drosophila development, the Hox protein Deformed (Dfd) maintains the boundary between the maxillary and mandibular head lobes by activating localized apoptosis. Dfd accomplishes this by directly activating the cell death promoting gene reaper (rpr). One other Hox gene, Abdominal-B (Abd-B), also regulates segment boundaries through the regional activation of apoptosis. Thus, one mechanism used by Drosophila Hox genes to modulate segmental morphology is to regulate programmed cell death, which literally sculpts segments into distinct shapes. This and other emerging evidence suggests that Hox proteins may often regulate the maintenance of segment boundaries.

Animals↗
PubMed2002

Hox Genes: it's all a matter of context.

Recent studies provide compelling new evidence that Hox gene effects depend on fine-structure spatial and temporal information. Further, in a specific cell type, only one or a few downstream genes may mediate Hox morphogenetic functions. If this is generally true, it will have important implications for how Hox regulatory networks operate and evolve.

Animals↗
PubMed2002

Hox protein mutation and macroevolution of the insect body plan.

A fascinating question in biology is how molecular changes in developmental pathways lead to macroevolutionary changes in morphology. Mutations in homeotic (Hox) genes have long been suggested as potential causes of morphological evolution, and there is abundant evidence that some changes in Hox expression patterns correlate with transitions in animal axial pattern. A major morphological transition in metazoans occurred about 400 million years ago, when six-legged insects diverged from crustacean-like arthropod ancestors with multiple limbs. In Drosophila melanogaster and other insects, the Ultrabithorax (Ubx) and abdominal A (AbdA, also abd-A) Hox proteins are expressed largely in the abdominal segments, where they can suppress thoracic leg development during embryogenesis. In a branchiopod crustacean, Ubx/AbdA proteins are expressed in both thorax and abdomen, including the limb primordia, but do not repress limbs. Previous studies led us to propose that gain and loss of transcriptional activation and repression functions in Hox proteins was a plausible mechanism to diversify morphology during animal evolution. Here we show that naturally selected alteration of the Ubx protein is linked to the evolutionary transition to hexapod limb pattern.

Amino Acid Sequence↗
PubMed2002

DEAF-1 function is essential for the early embryonic development of Drosophila.

The Drosophila protein DEAF-1 is a sequence-specific DNA binding protein that was isolated as a putative cofactor of the Hox protein Deformed (Dfd). In this study, we analyze the effects of loss or gain of DEAF-1 function on Drosophila development. Maternal/zygotic mutations of DEAF-1 largely result in early embryonic arrest prior to the expression of zygotic segmentation genes, although a few embryos develop into larvae with segmentation defects of variable severity. Overexpression of DEAF-1 protein in embryos can induce defects in migration/closure of the dorsal epidermis, and overexpression in adult primordia can strongly disrupt the development of eye or wing. The DEAF-1 protein associates with many discrete sites on polytene chromosomes, suggesting that DEAF-1 is a rather general regulator of gene expression.

Amino Acid Sequence↗
PubMed2002

Complete mutation analysis panel of the 39 human HOX genes.

BACKGROUND: The HOX gene family consists of highly conserved transcription factors that specify the identity of the body segments along the anteroposterior axis of the embryo. Because the phenotypes of mice with targeted disruptions of Hox genes resemble some patterns of human malformations, mutations in HOX genes have been expected to be associated with a significant number of human malformations. Thus far, however, mutations have been documented in only three of the 39 human HOX genes (HOXD13, HOXA13, and HOXA11) partly because current knowledge on the complete coding sequence and genome structure is limited to only 20 of the 39 human HOX genes. METHODS: Taking advantage of the human and mouse draft genome sequences, we attempted to characterize the remaining 19 human HOX genes by bioinformatic analysis including phylogenetic footprinting, the probabilistic prediction method, and comparison of genomic sequences with the complete set of the human anonymous cDNA sequences. RESULTS: We were able to determine the full coding sequences of 19 HOX genes and their genome structure and successfully designed a complete set of PCR primers to amplify the entire coding region of each of the 39 HOX genes from genomic DNA. CONCLUSIONS: Our results indicate the usefulness of bioinformatic analysis of the draft genome sequences for clinically oriented research projects. It is hoped that the mutation panel provided here will serve as a launchpad for a new discourse on the genetic basis of human malformations.

Animals↗
PubMed2002

Structure and expression patterns of Drosophila TULP and TUSP, members of the tubby-like gene family.

Tubby is a mouse gene that may provide a model for adult-onset obesity in humans. It is a member of a four gene family in mammals that collectively encode the Tubby-like proteins (TULPs), putative transcription factors which share similar 260 amino acid 'tubby domains' at their C-termini. The mammalian genome also encodes distant relatives of TULPs, which have been called TUSPs (tubby domain superfamily proteins). We have characterized the transcription unit of the single Drosophila TULP homolog, analyzed the expression pattern of the Drosophila TULP and TUSP genes, and determined the evolutionary relationships between the Drosophila proteins and members of the tubby domain superfamily in other organisms. Interestingly, like its mammalian homologs, Drosophila TULP is principally expressed in the embryonic central and peripheral nervous systems. This suggests that mammalian and Drosophila TULPs may possess some conserved functional properties in the nervous system. The Drosophila TUSP gene is also expressed in the central nervous system and olfactory organ but in few other peripheral sensory organs.

Adaptor Proteins, Signal Transducing↗