Most of the highly abundant genes were ribosomal, mitochondrial and housekeeping genes, whereas growth factors, transcription factors and regulators of gene expression were generally expressed at lower tpm.
Thus, genes generally expressed at low levels in normal samples, but over-expressed in a subset of cancer samples (although not all tumours), often represent potential drug targets of therapeutic interest, and may point to biologically different and diverse cancer subtypes that may require a specific form of individualized therapy.
The COX-1 is constitutively expressed in most tissues, generating basal levels of prostaglandins, whereas COX-2 is generally expressed at lower levels and can be induced by a variety of extracellular stimuli (Kujubu et al, 1991).
The second expectation concerns the overall correlation between the expression level and gene sequence conservation, where conserved genes are generally expressed at higher rates than fast evolving genes [ 24].
One hundred twenty-eight PC miRNA reads were less than 10 nt, which is consistent with a previous observation that nonconserved miRNAs are generally expressed at lower levels and represent tissue- or development-specific expression patterns [ 24].
They are generally expressed at low levels during early embryogenesis and begin to show increased expression beginning in late embryogenesis and throughout the three larval stages.
Transcript levels varied markedly (up to 3000-fold) but e1-a2 were generally expressed at higher levels than b3/b2-a2 (P = 0.05).
When expressed in Escherichia coli each of the woodrat proteins gave the characteristic maximum at 450 nm in a reduced carbon monoxide difference spectrum but generally expressed at lower levels than rat CYP2B1.
IL-1β and TNF-α mRNA was constitutively expressed whereas IL-6, IL-10 and IL-12 p40 mRNA was generally expressed at a lower level and was occasionally not detected.
This ratio is even lower than that of the least expressed non-TE genes (i.e., less than 2.5 average log2 intensity), indicating that non-TE rice genes not printed on the rice Affymetrix gene chip are generally expressed at very low levels.
Second, the CFTR protein is generally expressed at low levels in cells, which, combined with the paucity of reliable anti-CFTR antibodies, has made it difficult to establish the presence of significant CFTR expression in human neutrophils and how it may impact their function [87 89].
