retinal pigment epithelium is responsible for maintaining the structural integrity of the retina by an efficient defense against free radicals, photo-oxidative exposure and light energy. for this purpose the main rpe line of defense is melanosomes. melanin content of retinal pigment epithelium cells in adults and neonates reveals remarkable variations. in the current study we compared melanogen...

We have isolated a novel ascidian homeobox gene, designated AHox1, by screening the genomic DNA of Halocynthia roretzi with the Bombyx mori Antennapedia type homeobox as a probe. The AHox1 gene encodes a protein that consists of 741 amino acids. The homeobox of AHox1 is interrupted by 2 introns each of which is about 300 bp in length and it shows about 70% similarity at a deduced amino acid lev...

The NANOG homeobox gene plays a pivotal role in self-renewal and maintenance of pluripotency in human, mouse and other vertebrate embryonic stem cells, and in pluripotent cells of the blastocyst inner cell mass. There is a poorly studied and atypical homeobox locus close to the Nanog gene in some mammals which could conceivably be a cryptic paralogue of NANOG, even though the loci share only 20...

Many of the genes controlling segmentation and pattern formation in Drosophila contain a conserved 183 bp sequence known as the homeobox. Homeobox sequences have been found in a range of metazoan species, including the vertebrates mouse and man. This striking conservation suggests that homeobox genes may play a fundamental role in developmental processes. If this is the case then it might be ex...

The Hox-2.2 gene is one of a cluster of homeobox-containing genes on mouse chromosome 11. A cDNA clone containing the Hox-2.2 homeobox has been isolated from an adult spinal cord library. Our analysis of the Hox-2.2 cDNA and genomic clones indicates that there are at least two oxons and one intron. The largest open reading frame includes the homeobox and codes for a 224 amino acid protein of mo...

Homeobox-containing clones were isolated from a Lambda-ZAP cDNA library derived from somites of 2.5 day old chick embryos. The clones were identified by hybridization to the homeobox-containing Xenopus gene Xhoxl-A (1). Fourteen clones isolated from a screen of 3.3 xlO plaques of an amplified library contain homeobox sequences and some are highly conserved homologues of murine Hox genes. Sequen...

A novel homeobox gene, SOHo-1, was isolated from embryonic chicken retina. On embryonic day 2 (E2), SOHo-1 is expressed in the retina, posterolateral otic pit, and neural tube anterior to the spinal cord. On E4, SOHo-1 is expressed at high levels in anterior retina and low levels in posterior retina, suggestive of a role in patterning the anterior-posterior axis. It is also expressed on E4 in t...

The class I homeobox genes located in four clusters in mammalian genomes (HOX A, HOX B, HOX C, and HOX D) appear to play a major role in fetal development. Previous surveys of homeobox gene expression in human leukemic cell lines have shown that certain HOX A genes are expressed only in myeloid cell lines, whereas HOX B gene expression is largely restricted to cells with erythroid potential. We...

Commitments to developmental pathways are often made and maintained in groups of cells. Such commitments are conferred by the products of selector genes, many of which are homeobox genes. Homeobox genes can maintain their expression by directly autoregulating their own transcription. Here, we report a case where positive autoregulation of Ultrabithorax, a homeotic Drosophila gene, is at least p...

In eutherian mammals, sexual development hinges on the differentiation of the gonadal primordia into either testes or ovaries, in turn determined by the activity of the Y-linked gene Sry. Organogenesis of the gonads requires input from a complex network of morphogenetic signals, many of which are still uncharacterised. Homeobox genes are known to play important roles in embryo morphogenesis and...