Marianthi Kiriakidou

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A new paradigm of gene expression regulation has emerged recently with the discovery of microRNAs (miRNAs). Most, if not all, miRNAs are thought to control gene expression, mostly by base pairing with miRNA-recognition elements (MREs) found in their messenger RNA (mRNA) targets. Although a large number of human miRNAs have been reported, many of their mRNA(More)
microRNAs (miRNAs) bind to Argonaute (Ago) proteins and inhibit translation or promote degradation of mRNA targets. Human let-7 miRNA inhibits translation initiation of mRNA targets in an m(7)G cap-dependent manner and also appears to block protein production, but the molecular mechanism(s) involved is unknown and the role of Ago proteins in translational(More)
Steroidogenic acute regulatory protein (StAR) is required for efficient adrenal cortical and gonadal but not trophoblast steroid hormone synthesis. StAR gene expression in gonadal cells is stimulated by tropic hormones acting through the intermediacy of cAMP. DNA sequence analysis of the human StAR gene promoter revealed two motifs resembling binding sites(More)
A new paradigm of RNA-directed gene expression regulation has emerged recently, profound in scope but arresting in the apparent simplicity of its core mechanism. Cells express numerous small ( approximately 22 nucleotide) RNAs that act as specificity determinants to direct destruction or translational repression of their mRNA targets. These small RNAs arise(More)
MicroRNAs (miRNAs) have been implicated in B cell lineage commitment, regulation of T cell differentiation, TCR signalling, regulation of IFN signalling, and numerous other immunological processes. However, their function in autoimmunity, and specifically in systemic lupus erythematosus (SLE), remains poorly understood. B6.Sle123 is a spontaneous genetic(More)
A proximal element from the human StAR gene promoter, containing the sequence (-105)TATCCTTGAC(-95), was shown to confer responsiveness to 8-Br-cAMP in the presence of steroidogenic factor 1 (SF-1) when placed behind a minimal thymidine kinase promoter or an SV40 promoter and transfected into BeWo cells which normally lack StAR and SF-1. This element was(More)
Steroidogenic acute regulatory protein (StAR) plays a critical role in regulating the rate-limiting step in steroid hormone synthesis, cholesterol side-chain cleavage. StAR gene expression is transcriptionally controlled in the gonads by gonadotropic hormones via a cAMP second message. We have begun to analyze factors responsible for the transcriptional(More)
The rate-limiting step in steroid hormone production in the adrenal cortex and gonads, the translocation of cholesterol from the outer to the inner mitochondrial membranes, is mediated by the steroidogenic acute regulatory protein (StAR). Heretofore, the localization of StAR in human adult and fetal tissues has not been defined. To this end, expression of(More)
Stimulation of steroid-producing cells of the gonads and adrenals with tropic hormone results in a marked increase in steroid hormone synthesis within minutes. The rate-limiting step in this acute steroidogenic response is the transport of cholesterol from the outer to the inner mitochondrial membrane, where the first committed step in steroid synthesis is(More)
MicroRNAs (miRNAs) are small, non-coding RNAs that regulate gene expression primarily at the post-transcriptional level. Emerging evidence supports a regulatory role for miRNAs in the immune response and autoimmunity. In this work, we investigated the implication of miR-21 in the experimentally inducible bm12→B6 cGVHD model of systemic lupus erythematosus(More)