["Cis" and "trans" regulator elements of transcription]. / Les éléments "cis" et "trans"-régulateurs de la transcription.

ABSTRACT

The 5'-flanking region of genes is involved in transcription regulaton. Multiple nucleotidic cis-acting sites are spread out over a region of 400 bp, (mostly) upstream of the start point. Examples are given with TATA box, GC box, CCAAT box and some octamers. Transcription factors recognize cis-acting sites and bind to them. Some are required for transcription initiation. Others affect (usually enhance) the rate of initiation. Trans-regulator proteins contain two domains. One is responsible for binding to DNA (as for instance Zn fingers, Leu zipper, positive homeotic domain). The other one is responsible for activity on transcription (as for instance rich in Gln, rich in Pro, acidic alpha-helix domain). Some technics used for determination of the site of transcription initiation and of protein fixation on DNA are briefly described. It is hoped that a better comprehension of transcription mechanisms will offer new possibilities of investigation for acting in some varieties of protein synthesis dysfunctionnements.