Identification, sequence and expression of a crustacean cardioactive peptide (CCAP) gene in the moth Manduca sexta.

The crustacean cardioactive peptide (CCAP) gene was isolated from the tobacco hawkmoth Manduca sexta. The gene has an open reading frame of 125 amino acid residues containing a single, complete copy of CCAP. Analysis of the gene structure revealed three introns interrupting the coding region. A comparison of the M. sexta CCAP gene with the Drosophila melanogaster genome database reveals significant similarities in sequence and gene structure. The spatial and temporal expression patterns of the CCAP gene in the M. sexta central nervous system were determined in all major post-embryonic stages using in situ hybridization techniques. The CCAP gene is expressed in a total of 116 neurons in the post-embryonic M. sexta central nervous system. Nine pairs of cells are observed in the brain, 4.5 pairs in the subesophageal ganglion, three pairs in each thoracic ganglion (T1-T3), three pairs in the first abdominal ganglion (A1), five pairs each in the second to sixth abdominal ganglia (A2-A6) and 7.5 pairs in the terminal ganglion. The CCAP gene is expressed in every ganglion in each post-embryonic stage, except in the thoracic ganglia of first- and second-instar larvae. The number of cells expressing the CCAP gene varies during post-embryonic life, starting at 52 cells in the first instar and reaching a maximum of 116 shortly after pupation. One set of thoracic neurons expressing CCAP mRNA shows unusual variability in expression levels immediately prior to larval ecdysis. Using previously published CCAP immunocytochemical data, it was determined that 91 of 95 CCAP-immunopositive neurons in the M. sexta central nervous system also express the M. sexta CCAP gene, indicating that there is likely to be only a single CCAP gene in M. sexta.

Gene defect in ectodermal dysplasia implicates a death domain adapter in development.

Members of the tumour-necrosis factor receptor (TNFR) family that contain an intracellular death domain initiate signalling by recruiting cytoplasmic death domain adapter proteins. Edar is a death domain protein of the TNFR family that is required for the development of hair, teeth and other ectodermal derivatives. Mutations in Edar-or its ligand, Eda-cause hypohidrotic ectodermal dysplasia in humans and mice. This disorder is characterized by sparse hair, a lack of sweat glands and malformation of teeth. Here we report the identification of a death domain adapter encoded by the mouse crinkled locus. The crinkled mutant has an hypohidrotic ectodermal dysplasia phenotype identical to that of the edar (downless) and eda (Tabby) mutants. This adapter, which we have called Edaradd (for Edar-associated death domain), interacts with the death domain of Edar and links the receptor to downstream signalling pathways. We also identify a missense mutation in its human orthologue, EDARADD, that is present in a family affected with hypohidrotic ectodermal dysplasia. Our findings show that the death receptor/adapter signalling mechanism is conserved in developmental, as well as apoptotic, signalling.

A novel X-linked disorder of immune deficiency and hypohidrotic ectodermal dysplasia is allelic to incontinentia pigmenti and due to mutations in IKK-gamma (NEMO).

Hypohidrotic ectodermal dysplasia (HED), a congenital disorder of teeth, hair, and eccrine sweat glands, is usually inherited as an X-linked recessive trait, although rarer autosomal dominant and recessive forms exist. We have studied males from four families with HED and immunodeficiency (HED-ID), in which the disorder segregates as an X-linked recessive trait. Affected males manifest dysgammaglobulinemia and, despite therapy, have significant morbidity and mortality from recurrent infections. Recently, mutations in IKK-gamma (NEMO) have been shown to cause familial incontinentia pigmenti (IP). Unlike HED-ID, IP affects females and, with few exceptions, causes male prenatal lethality. IKK-gamma is required for the activation of the transcription factor known as "nuclear factor kappa B" and plays an important role in T and B cell function. We hypothesize that "milder" mutations at this locus may cause HED-ID. In all four families, sequence analysis reveals exon 10 mutations affecting the carboxy-terminal end of the IKK-gamma protein, a domain believed to connect the IKK signalsome complex to upstream activators. The findings define a new X-linked recessive immunodeficiency syndrome, distinct from other types of HED and immunodeficiency syndromes. The data provide further evidence that the development of ectodermal appendages is mediated through a tumor necrosis factor/tumor necrosis factor receptor-like signaling pathway, with the IKK signalsome complex playing a significant role.