Structure of the mouse leukaemia inhibitory factor receptor gene: regulated expression of mRNA encoding a soluble receptor isoform from an alternative 5′ untranslated region

Abstract

The low-affinity leukaemia inhibitory factor receptor (LIF-R) is a component of cell-surface receptor complexes for the multifunctional cytokines leukaemia inhibitory factor, ciliary neurotrophic factor, oncostatin M and cardiotrophin-1. Both soluble and transmembrane forms of the protein have been described and several LIF-R mRNAs have been reported previously. In order to determine the coding potential of LIF-R mRNAs we have isolated and characterized the mouse LIF-R gene. mRNA encoding soluble LIF-R (sLIF-R) is formed by inclusion of an exon in which polyadenylation signals are provided by a B2 repeat. This exon is located centrally within the LIF-R gene but is excluded from the transmembrane LIF-R mRNA by alternative splicing. The transmembrane receptor is encoded by 19 exons distributed over 38 kb. Two distinct 5' non-coding exons have been identified, indicating the existence of alternative promoters. One of these is G/C rich and possesses a consensus initiator sequence as well as potential Sp1 binding sites. Expression of exon 1 from this promoter occurs in a wide variety of tissues, whereas expression of the alternative 5' untranslated region (exon 1a) is normally restricted to liver, the principal source of sLIF-R. During pregnancy expression of exon 1a becomes detectable also in the uterus. Expression of exon 1a increases dramatically during gestation and is accompanied by a similar quantitative rise in expression of sLIF-R mRNA. These findings establish that expression of LIF-R is under complex transcriptional control and indicate that regulated expression of the soluble cytokine receptor isoform may be due principally to an increase in the activity of a dedicated promoter.

Hypoxia-inducible Factor-1α Inhibits Self-renewal of Mouse Embryonic Stem Cells in Vitro via Negative Regulation of the Leukemia Inhibitory Factor-STAT3 Pathway

“…An earlier report (19) shows that HIF-1␣ acts as a transcriptional repressor of certain genes by direct binding to specific reverse HREs (rHREs), HREs on the antisense strand. Interestingly, the mouse LIFR promoter contains three potential rHREs (DNA consensus 5Ј-TGCAC-3Ј located at positions Ϫ894 to Ϫ890, Ϫ739 to Ϫ735, and Ϫ553 to Ϫ549 from the translation start site) (20) (Fig. 3B).…”

Distinctive higher-order chromatin structure at mammalian centromeres

“…The probes used were mouse minor satellite R198 (16), mouse major satellite (17), and a B2 interspersed repeat (18). The specificity of the satellite probes was confirmed by standard fluorescence in situ hybridization (FISH) analysis (19) of metaphase spreads of NIH 3T3 cells.…”

“…DNA isolated from individual gradient fractions was electrophoresed in an agarose gel. After fluorescence scanning, the DNA in the gel was transferred onto a nylon membrane and hybridized in succession with probes for mouse minor satellite DNA (16), mouse major satellite DNA (17), and a B2 interspersed repeat (18). The size of the DNA contained in the chromatin fibers recovered from each gradient fraction was determined from densitometer traces of lanes from the ethidium bromide-stained gel and from each of the hybridized filters (see Fig.…”

Leukemia Inhibitory Factor and Its Receptor Promote Adipocyte Differentiation via the Mitogen-activated Protein Kinase Cascade

“…Quantification of the hybridization signal was performed using a PhosphorImager apparatus (Fujix Bas 1000). Probes for LIF, ob, GAPDH, and LIF receptor have been described (22,23). The C/EBP␤ and C/EBP␦ cDNAs were provided by S. L. McKnight (Tularik Inc., South San Francisco).…”