Differential transcription of multiple copies of a silk worm gene encoding tRNA

Fournier, Alain and Taneja, Reshma and Gopalkrishnan, Rahul and Prudhomme, Jean-Claude and Gopinathan, Karumathil P (1993) Differential transcription of multiple copies of a silk worm gene encoding tRNA. In: Gene, 134 (2). pp. 183-190.

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Abstract

Ten different tRNAGly1 genes from the silk worm, Bombyx mori, have been cloned and characterized. These genes were transcribed in vitro in homologous nuclear extracts from the posterior silk gland (PSG) or nuclear extracts derived from the middle silk gland or ovarian tissues. Although the transcription levels were much higher in the PSG nuclear extracts, the transcriptional efficiency of the individual genes followed a similar pattern in all the extracts. Based on the levels of in vitro transcription, the ten tRNAGly1 genes could be divided into three groups, viz., those which were transcribed at very high levels (e.g., clone pR8), high to medium levels (e.g., pBmil, pBmpl, pBmhl, pBmtl) and low to barely detectable levels (e.g., pBmsl, pBmjl and pBmkl). The coding sequences of all these tRNA genes being identical, the differential transcription suggested that the flanking sequences modulate their transcriptional efficiency. The presence of positive and negative regulatory elements in the 5' flanking regions of these genes was confirmed by transcription competition experiments. A positive element was present in the immediate upstream A + T-rich sequences in all the genes, but no consensus sequences correlating to the transcriptional status could be generated. The presence of negative elements on the other hand was indicated only in some of the genes and therefore may have a role in the differential transcription of these tRNAGly genes in vivo.

Item Type:	Journal Article
Publication:	Gene
Publisher:	Elsevier Science
Additional Information:	Copyright of this article belongs to Elsevier Science.
Keywords:	Bombyx mori;gene family;negative regulation;positive regulation;RNA polymerase III transcription;regulatory elements;tissue specificity;transcription factors; transcription regulation.
Department/Centre:	Division of Biological Sciences > Microbiology & Cell Biology
Date Deposited:	10 Feb 2011 07:31
Last Modified:	10 Feb 2011 07:31
URI:	http://eprints.iisc.ac.in/id/eprint/35401

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