MicroRNAs: reguladores clave de la expresión génica

El descubrimiento de nuevos sistemas de regulación génica bajo el control de RNA pequeños ha tenido un impacto significativo en la biología molecular. Los Micro- RNA (miRNA) son una clase de RNA pequeños no codificantes (aquellos que no codifican para proteínas) que regulan la expresión génica pos-transcripcional. Se unen por apareamiento imperfecto a sus RNA mensajeros blanco (RNAm) , generalmente en la región 3´-no traducible, bloqueando la síntesis de proteínas por desestabilización del RNAm y represión traduccional. Un gran número de miRNA han sido identificados en el genoma de varias especies incluyendo el humano, y el número de miRNA sigue incrementándose debido a los esfuerzos combinados de la biología molecular y a la predicción bioinformática. Se ha descrito que estas moléculas regulan funciones celulares, por lo que no es sorprendente que los miRNA estén implicados en una gran variedad de enfermedades, como el cáncer y la diabetes mellitus. El propósito de esta revisión es brindar información actualizada sobre la síntesis de los miRNA y los avances en el entendimiento de los mecanismos de silenciamiento génico mediados por los miRNA, así como su uso potencial para el diagnóstico de enfermedades y su terapia

Molecular cloning of the myo-inositol oxygenase gene from the kidney of baboons

Abstract. The enzyme myo-Inositol oxygenase (MIOX) is also termed ALDRL6. It is a kidney‑specific member of the aldo‑keto reductase family. MIOX catalyzes the first reaction involved in the myo‑inositol metabolism signaling pathway and is fully expressed in mammalian tissues. MIOX catalyzes the oxidative cleavage of myo‑Inositol and its epimer, D-chiro-Inositol to D-glucuronate. The dioxygen-dependent cleavage of the C6 and C1 bond in myo‑Inositol is achieved by utilizing the Fe2+/Fe3+ binuclear iron center of MIOX. This enzyme has also been implicated in the complications of diabetes, including diabetic nephropathy. The MIOX gene was amplified with reverse transcription‑polymerase chain reaction from baboon tissue samples, and the product was cloned and sequenced. MIOX expression in the baboon kidney is described in the present study. The percentages of nucleotide and amino acid similarities between baboons and humans were 95 and 96%, respectively. The MIOX protein of the baboon may be structurally identical to that of humans. Furthermore, the evolutionary changes, which have affected these sequences, have resulted from purifying forces. Key words: animal models, gene expression, kidney, myo-inositol oxygenase, Old World monke

Molecular evolution and expression profile of the chemerine encoding gene RARRES2 in baboon and chimpanzee

BACKGROUND: Chemerin, encoded by the retinoic acid receptor responder 2 (RARRES2) gene is an adipocytesecreted protein with autocrine/paracrine functions in adipose tissue, metabolism and inflammation with a recently described function in vascular tone regulation, liver, steatosis, etc. This molecule is believed to represent a critical endocrine signal linking obesity to diabetes. There are no data available regarding evolution of RARRES2 in non-human primates and great apes. Expression profile and orthology in RARRES2 genes are unknown aspects in the biology of this multigene family in primates. Thus; we attempt to describe expression profile and phylogenetic relationship as complementary knowledge in the function of this gene in primates. To do that, we performed A RT-PCR from different tissues obtained during necropsies. Also we tested the hypotheses of positive evolution, purifying selection, and neutrality. And finally a phylogenetic analysis was made between primates RARRES2 protein. RESULTS: RARRES2 transcripts were present in liver, lung, adipose tissue, ovary, pancreas, heart, hypothalamus and pituitary tissues. Expression in kidney and leukocytes were not detectable in either species. It was determined that the studied genes are orthologous. CONCLUSIONS: RARRES2 evolution fits the hypothesis of purifying selection. Expression profiles of the RARRES2 gene are similar in baboons and chimpanzees and are also phylogenetically related