The organellar genome and metabolic potential of the hydrogen-producing mitochondrion of Nyctotherus ovalis.

It is generally accepted that hydrogenosomes (hydrogen-producing organelles) evolved from a mitochondrial ancestor. However, until recently, only indirect evidence for this hypothesis was available. Here, we present the almost complete genome of the hydrogen-producing mitochondrion of the anaerobic ciliate Nyctotherus ovalis and show that, except for the notable absence of genes encoding electron transport chain components of Complexes III, IV, and V, it has a gene content similar to the mitochondrial genomes of aerobic ciliates.

Polychaete trunk neuroectoderm converges and extends by mediolateral cell intercalation.

During frog and fish development, convergent extension movements transform the spherical gastrula into an elongated neurula. Such transformation of a ball- into a worm-shaped embryo is an ancestral and fundamental feature of bilaterian development, yet this is modified or absent in the protostome model organisms Caenorhabditis or Drosophila. In the polychaete annelid Platynereis dumerilii, early embryonic and larval stages resemble a sphere that subsequently elongates into worm shape.

Large-scale expression screening by automated whole-mount in situ hybridization.

Gene expression profiling is an important component of functional genomics. We present a time and cost efficient high-throughput whole-mount in situ technique to perform a large-scale gene expression analysis in medaka fish (Oryzias latipes) embryos. Medaka is a model system ideally suited for the study of molecular genetics of vertebrate development.

Clone-based systematic haplotyping (CSH): a procedure for physical haplotyping of whole genomes.

We present a novel methodology to determine the phase of single-nucleotide polymorphisms (SNPs) on a chromosome, which we term clone-based systematic haplotyping (CSH). The CSH procedure is based on separating the allelic chromosomes of a diploid genome by fosmid/cosmid cloning, and subsequent SNP typing of 96 clone pools, each representing approximately 10% of the genome. The pools are screened by PCR for the sequence of interest, followed by SNP typing on the PCR products using the GOOD assay.

Functional and comparative analysis of globin loci in pufferfish and humans.

To further our understanding of the regulation of vertebrate globin loci, we have isolated cosmids containing alpha- and beta-globin genes from the pufferfish Fugu rubripes. By DNA fluorescence in situ hybridization (FISH) analysis, we show that Fugu contains 2 distinct hemoglobin loci situated on separate chromosomes. One locus contains only alpha-globin genes (alpha-locus), whereas the other also contains a beta-globin gene (alpha beta-locus).

Isolation and characterization of cold-shock domain protein genes, Oryzias latipes Y-box protein 2 (OlaYP2) and Fugu rubripes Y-box protein 1 (FruYP1), in medakafish and pufferfish.

The Y-box protein (YP) family shares a nucleic acid binding domain, called cold-shock domain, that has been evolutionarily highly conserved from bacteria to human. The different YPs identified so far in vertebrates are thought to function as transcriptional activators, transcriptional repressors and/or translational repressors. Medakafish and pufferfish are very suitable vertebrate models for the study of developmental genetics and comparative genomics, respectively.

Functional equivalency of amphioxus and vertebrate Pax258 transcription factors suggests that the activation of mid-hindbrain specific genes in vertebrates occurs via the recruitment of Pax regulatory elements.

Pax genes encode transcription factors that control key developmental decisions in various animal phyla. The Pax2/5/8 subfamily plays a key role in specification and/or maintenance of vertebrate mid-hindbrain boundary (MHB) region by directly regulating expression of other genes, most notably En2. In the invertebrate chordate amphioxus, expression of AmphiPax2/5/8 is found in many sites that are homologous to the regions of the vertebrate embryo expressing orthologous genes Pax2, Pax5 or Pax8.