Open AccessSequence divergence and selection of cap sites in the rat γ‐crystallin gene family
Author(s) -
LEEN Rob W.,
KASTROP Peter M. M.,
ROOZENDAAL Kees E. P.,
SCHOENMAKERS John G. G.
Publication year - 1986
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1986.tb09657.x
Subject(s) - gene , biology , tata box , genetics , primer extension , intron , transcription (linguistics) , exon , consensus sequence , microbiology and biotechnology , rna , promoter , peptide sequence , gene expression , linguistics , philosophy
The transcription initiation sites of the six rat γ‐crystallin genes were mapped by combining the results of primer extension and S1 nuclease mapping experiments. To obtain more accurate results from the S1 nuclease mapping experiments, intron‐deleted clones were constructed by a novel and efficient modification of existing methods involving the use of primer extension products to seal the exons. Four of the six γ‐crystallin genes have multiple transcription start sites. The major and most of the minor transcripts start with an adenosine. Analysis of the 5′ flanking sequences of the γ‐crystallin genes shows that the sequence determining the position of the cap site is merely ‐CA‐ and that its optimal distance from the first T of the TATA box is 32 base pairs. Our data further suggest that an A to G transition in the first two base pairs of the Goldberg/Hogness box of one of the genes does not affect the position of its major cap site. This, together with the fact that most minor transcription start sites are located upstream from the major cap sites, suggests that in the long TATA boxes of the rat γ‐crystallin genes the major RNA polymerase ‘trap site’ is not directly at the beginning of the TATA sequence.