Transcriptional modulation of entire chromosomes: dosage compensation

Journal of genetics

JOHN C. LUCCHESI^1¹ 

[1] Department of Biology, Emory University, Atlanta, GA 30322, USA^1

关键词: dosage compensation;    sex chromosomes;    sex determination;    Drosophila;    Caenorhabditis;    mammals.;   

DOI  :  

学科分类：生物科学（综合）

来源: Indian Academy of Sciences

【 摘 要 】

Dosage compensation is a regulatory system designed to equalize the transcription output of the genes of the sex chromosomes that are present in different doses in the sexes (X or Z chromosome, depending on the animal species involved). Different mechanisms of dosage compensation have evolved in different animal groups. In Drosophila males, a complex (male-specific lethal) associates with the X chromosome and enhances the activity of most X-linked genes by increasing the rate of RNAPII elongation. In Caenorhabditis, a complex (dosage compensation complex) that contains a number of proteins involved in condensing chromosomes decreases the level of transcription of both X chromosomes in the XX hermaphrodite. In mammals, dosage compensation is achieved by the inactivation, early during development, of most X-linked genes on one of the two X chromosomes in females. The mechanism involves the synthesis of an RNA (Tsix) that protects one of the two Xs from inactivation, and of another RNA (Xist) that coats the other X chromosome and recruits histone and DNA modifying enzymes. This review will focus on the current progress in understanding the dosage compensation mechanisms in the three taxa where it has been best studied at the molecular level: flies,round worms and mammals.

【 授权许可】

CC BY