Relationship between amino acid composition and gene expression in the mouse genome

<p>Abstract</p> <p>Background</p> <p>Codon bias is a phenomenon that refers to the differences in the frequencies of synonymous codons among different genes. In many organisms, natural selection is considered to be a cause of codon bias because codon usage in highly expressed genes is biased toward optimal codons. Methods have previously been developed to predict the expression level of genes from their nucleotide sequences, which is based on the observation that synonymous codon usage shows an overall bias toward a few codons called major codons. However, the relationship between codon bias and gene expression level, as proposed by the translation-selection model, is less evident in mammals.</p> <p>Findings</p> <p>We investigated the correlations between the expression levels of 1,182 mouse genes and amino acid composition, as well as between gene expression and codon preference. We found that a weak but significant correlation exists between gene expression levels and amino acid composition in mouse. In total, less than 10% of variation of expression levels is explained by amino acid components. We found the effect of codon preference on gene expression was weaker than the effect of amino acid composition, because no significant correlations were observed with respect to codon preference.</p> <p>Conclusion</p> <p>These results suggest that it is difficult to predict expression level from amino acid components or from codon bias in mouse.</p

A systematic review and meta-analysis of bone metabolism in prostate adenocarcinoma

<p/> <p>Background</p> <p>Osteoporosis could be associated with the hormone therapy for metastatic prostate carcinoma (PCa) and with PCa <it>per se</it>. The objective of this review is to determine the incidence of bone loss and osteoporosis in patients with PCa who are or are not treated with hormone therapy (ADT).</p> <p>Methods</p> <p>The Medline, Embase, Cancerlit, and American Society of Clinical Oncology Abstract databases were searched for published studies on prostate cancer and bone metabolism. The outcomes assessed were: fracture, osteoporosis and osteopenia.</p> <p>Results</p> <p>Thirty-two articles (116,911 participants) were included in the meta-analysis. PCa patients under ADT had a higher risk of osteoporosis (RR, 1.30; <it>p </it>< 0.00001) and a higher risk of fractures (RR, 1.17; <it>p </it>< 0.00001) as compared to patients not under ADT. The total bone mineral density was lower in patients under ADT when compared with patients not under ADT (<it>p </it>= 0.031) but it was similar to bone mineral density found in healthy controls (<it>p </it>= 0.895). The time of androgen deprivation therapy correlated negatively with lumbar spine and total hip bone mineral density (Spearman's rho = -0.490 and -0.773; <it>p </it>= 0.028 and 0.001, respectively) and with total hip <it>t </it>score (Spearman's rho = -0.900; <it>p </it>= 0.037).</p> <p>Conclusion</p> <p>We found consistent evidence that the use of androgen deprivation therapy in patients with PCa reduces bone mineral density, increasing the risk of fractures in these patients.</p