Rougvie AE (2009) Sci Signal "miRNA regulation through ligand occupancy of a nuclear hormone receptor."

Rougvie AE

[Sci Signal, 2009]

MicroRNAs (miRNAs) posttranscriptionally regulate gene expression, but the factors that direct transcription of miRNAs are not well characterized. Activation versus repression of key developmental miRNAs in Caenorhabditis elegans is directly mediated by ligand occupancy of a nuclear hormone receptor that acts to couple nutrient availability to developmental programs.

Rougvie AE et al. (1995) Development "The heterochronic gene lin-29 encodes a zinc finger protein that controls a terminal differentiation event in Caenorhabditis elegans."

Rougvie AE, Ambros VR

[Development, 1995]

A hierarchy of heterochronic genes, lin-4, lin-14, lin-28 and lin-29, temporally restricts terminal differentiation of Caenorhabitis elegans hypodermal seam cells to the final molt. This terminal differentiation event involves cell cycle exit, cell fusion and the differential regulation of genes expressed in the larval versus adult hypodermis, lin-29 is the most downstream gene in the developmental timing pathway and thus it is the most direct known regulator of these diverse processes, We show that lin-29 encodes a protein with five zinc fingers of the (Cys)(2)-(HiS)(2) class and thus likely controls these processes by regulating transcription in a stage-specific manner, Consistent with this role, a lin-29 fusion protein binds in vitro to the 5' regulatory sequences necessary in vivo for expression of col-19, a collagen gene expressed in the adult hypodermis. lin-29 mRNA is detected in the first larval stage and increases in abundance through subsequent larval stages until the final molt, w hen lin-29 activity is required for terminal differentiation.

Abdel-Wahab N et al. Mol Biochem Parasitol "OvB20, an Onchocerca volvulus-cloned antigen selected by differential immunoscreening with vaccination serum in a cattle model of onchocerciasis."

Wu Y, Abdel-Wahab N, Tuan RS, Kuo YM, Bianco AE

[Mol Biochem Parasitol]

A cDNA of Onchocerca volvulus has been isolated by differential immunoscreening of an adult worm expression library using sera raised in cattle against the related species, O. lienalis. It was selected because of its recognition by antibodies from cattle immunized with irradiated third-stage (L3) larvae and not by antibodies from animals infected with non-irradiated larvae. The original 311-bp clone was used to isolate a 1478-bp cDNA. Designated OvB20, this codes for 460 amino acid residues, hybridizes with a approximately 1.6 kBp transcript and appears to be transcribed from a filarial-specific, single copy gene. It is expressed in developing stages from embryo to L4 larva, but not in the adult. The product of OvB20 appears to undergo co- or post-translational processing: in vitro transcription and translation give rise to a polypeptide consistent with the deduced amino acid sequence (approximately 52 kDa), whilst products of 52 and 65 kDa are detected in larvae by immunoblotting and following in vitro translations to which exogenous microsomes have been added. A 42-kDa protein was also detected in all in vitro translations. No homologous genes were found in the computer databases, although there are regions of weak sequence similarity with C-reactive proteins. The functional role of OvB20 may warrant further attention, as it has recently been shown that the recombinant protein confers host protection against a related rodent filaria following active immunization (Taylor, M.J., Abdel-Wahab, N., Wu, Y., Jenkins, R.E. and Bianco, A.E. (1995) Onchocerca volvulus larval antigen, OvB20 induces partial protection in a rodent model of onchocerciasis. Infect. Immun. 63, 4417-4422).