[1] Brachet was appointed Professor of Animal Morphology and General Biology at the Université libre de Bruxelles ('Free University of Brussels', the institution operating between 1834 and 1969) and Research Director of the International Laboratory for Genetics and Biophysics in Naples.
[2] In 1933 Brachet was able to show that DNA was found in chromosomes and that RNA was present in the cytoplasm of all cells.
At the same time as Torbjörn Caspersson he independently showed that RNA plays an active role in protein synthesis.
Brachet demonstrated that differentiation is preceded by the formation of new ribosomes and accompanied by the release from the nucleus of a wave of new messenger RNA.
[4] In 1948 Jean Brachet was awarded the Francqui Prize for Biological and Medical Sciences and in 1953 he received the Albert Brachet Prize [fr] from the Royal Academy of Belgium for the best original work in embryology, an award instituted in honour of his father.