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Title: Characterisation of a novel retroviral LTR-containing member of the pregnancy-specific glycoprotein locus in the mouse
Author: Collins, B.
Awarding Body: University of Cambridge
Current Institution: University of Cambridge
Date of Award: 2000
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The insertion, via retrotransposition of IAP DNA sequences in the promoter region of the mouse agouti gene induces de novo parental origin dependent expression at this locus, suggesting that IAPs may contain autonomous imprinting elements. Interest in placental expression of IAPs was further stimulated by the serendipitous observation that, compared to wildtype, placentas from mouse embryos maternally disomic for distal chromosome 7 (Mat-di7) exhibit a double dose of an abundant ~2kb transcript on northern blots hybridised to an IAP-LTR probe. Since the IAP-LTR-containing transcript (LTRct) did not hybridise to IAP probes other than LTR DNA sequences, we hypothesised that transcription at this locus was driven by an IAP-LTR promoter, suggesting a mechanistic parallel with the imprinted agouti locus mutants. We screened a C57BL/6J placental cDNA library using a two-stage subtractive screening approach. Full sequencing of the LTRct clones showed them to be from a novel member of the previously described pregnancy specific glycoprotein (Psg) multigene family. However, unlike agouti locus mutants, the LTR is at the 3' end of the Psg sequence and provides the polyadenylation signal for the transcript. In addition, a previously identified EST (Psg23) has 100% identity with LTRct over 314 bases, and we hereafter refer to LTRct as Psg23LTR. The LTR insertion is widely distributed among common inbred strains but absent from CBA and M. castaneus, facilitating direct analysis of imprinted status of the transcript. In interspecies crosses, we found that this transcript is not imprinted.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available