[
Trends Pharmacol Sci,
2000]
Nuclear receptors represent a large class of ligand-activated transcriptional regulators; about 70 members of this protein family have been cloned from mammalian or insect species. Thus, it came as a great surprise when the recent completion of the Caenorhabditis elegans genome revealed at least 228 genes for nuclear receptors. Clearly, some of these receptors are homologues of known receptors, but most lack homologues in other species. Whether these receptors possess homologues in mammalian species is of great interest; if these do exist, the size of the nuclear receptor superfamily could also expand dramatically in humans.
[
Trends Pharmacol Sci,
2001]
Complete nucleotide sequences are now available for different species of the animal kingdom: Caenorhabditis elegans - a nematode, Drosophila - an insect, and humans - a mammal. Such information makes it possible to compare the set of nuclear receptors found in these organisms, and to discuss the possible reasons for the differences observed. The human genome sequencing identified few new receptors, which implies that most nuclear receptors have now been found. However, information about polymorphisms and regulating sequences, obtained through genomic sequencing, will be important for understanding receptor function and disease mechanisms. The surprisingly large number of nuclear receptors in C. elegans might have implications for the development of pharmaceuticals and the understanding of the function of these animals. By contrast, Drosophila has few nuclear receptors; however, examination of the unique nuclear receptors provides information about the function of these receptors.
[
Lakartidningen,
2002]
Recently the complete genomic sequences for three very different multicellular organisms have been published, from one nematode (Caenorhabditis elegans), one fly (Drosophila melanogaster) and human (Homo sapiens). Of course, this means a breakthrough in many ways for biological research. Summarised in this article are the findings made using these genomic sequences regarding the protein family of nuclear receptors. This is a group of transcription factors involved in many important biological processes, i.e. regulation of cholesterol homeostasis and fertility; classical members of this protein family are, amongst others, the receptors for estradiol and progesterone.