Biomedical subjects

A Eizinger

Publications and source records attributed to A Eizinger.

4 recordsLinked to original sources

PubMed2001

A gene expression map for Caenorhabditis elegans.

We have assembled data from Caenorhabditis elegans DNA microarray experiments involving many growth conditions, developmental stages, and varieties of mutants. Co-regulated genes were grouped together and visualized in a three-dimensional expression map that displays correlations of gene expression profiles as distances in two dimensions and gene density in the third dimension. The gene expression map can be used as a gene discovery tool to identify genes that are co-regulated with known sets of genes (such as heat shock, growth control genes, germ line genes, and so forth) or to uncover previously unknown genetic functions (such as genomic instability in males and sperm caused by specific transposons).

Algorithms↗

PubMed1999

Evolutionary change in the functional specificity of genes.

Species throughout the animal kingdom share not only housekeeping but also many key regulatory genes. Nonetheless, species differ from one another developmentally and thus, also morphologically. One of the general aims of comparative developmental genetics is to understand how similar molecules can generate the known diversity of biological form. Here, we argue that gene function can change in different ways during the evolution of developmental processes. Genes can be recruited to serve completely new functions in a new regulatory linkage (co-option), they can change their molecular specificity while remaining in the original (homologous) developmental program and can, at the same time, retain other functions. We describe evidence for such evolutionary patterns based on the comparison of loss-of-function mutations of homologous genes of the two free-living nematodes Caenorhabditis elegans and Pristionchus pacificus. Ultimately, it is the interplay of conservation and change of the specificity of genes and genetic networks that generates developmental novelty over evolutionary time.

Animals↗

PubMed1998

The Pristionchus HOX gene Ppa-lin-39 inhibits programmed cell death to specify the vulva equivalence group and is not required during vulval induction.

In the two nematode species Caenorhabditis elegans and Pristionchus pacificus the vulva equivalence group in the central body region is specified by the Hox gene lin-39. C. elegans lin-39 mutants are vulvaless and the vulval precursor cells fuse with the surrounding hypodermis, whereas in P. pacificus lin-39 mutants the vulval precursor cells die by apoptosis. Mechanistically, LIN-39 might inhibit non-vulval fate (cell fusion in C. elegans, apoptosis in P. pacificus), promote vulval fate or do both. To study the mechanism of lin-39 function, we isolated P. pacificus cell death mutants and identified mutations in ced-3. Surprisingly, P. pacificus ced-3; lin-39 double mutants form a functional vulva in the absence of LIN-39 activity. Thus, in P. pacificus lin-39 specifies the vulva equivalence group by inhibiting programmed cell death. Furthermore, these data reveal an important difference in a later function of lin-39 between the two species. In C. elegans, LIN-39 specifies vulval cell fates in response to inductive RAS signaling, and in P. pacificus LIN-39 is not required for vulval induction. Thus, the comparative analysis indicates that lin-39 has distinct functions in both species although the gene is acting in a homologous developmental system.

Animals↗

PubMed1997

The homeotic gene lin-39 and the evolution of nematode epidermal cell fates.

The fate of ventral epidermal cells differs among nematode species. Nonvulval cells fuse with the epidermis in Caenorhabditis elegans, whereas the homologous cells undergo apoptosis in Pristionchus pacificus. The homeotic gene lin-39 is involved in the regulation of these epidermal cell fates. In Caenorhabditis, lin-39 prevents cell fusion of potential vulval cells and specifies the vulva equivalence group. Pristionchus vulvaless mutants that displayed apoptosis of the vulval precursor cells were isolated, and point mutations in lin-39 were identified. Thus, the evolution of these epidermal cell fates is driven by different intrinsic properties of homologous cells.

Amino Acid Sequence↗