AFF4

The protein encoded by this gene belongs to the AF4 family of transcription factors involved in leukemia. It is a component of the positive transcription elongation factor b (P-TEFb) complex. A chromosomal translocation involving this gene and MLL gene on chromosome 11 is found in infant acute lymphoblastic leukemia with ins(5;11)(q31;q31q23). [provided by RefSeq, Oct 2011]

Full Name

AF4/FMR2 Family Member 4

Function

Key component of the super elongation complex (SEC), a complex required to increase the catalytic rate of RNA polymerase II transcription by suppressing transient pausing by the polymerase at multiple sites along the DNA. In the SEC complex, AFF4 acts as a central scaffold that recruits other factors through direct interactions with ELL proteins (ELL, ELL2 or ELL3) and the P-TEFb complex. In case of infection by HIV-1 virus, the SEC complex is recruited by the viral Tat protein to stimulate viral gene expression.

Biological Process

Regulation of gene expression
Spermatid development
Transcription by RNA polymerase II
Transcription elongation from RNA polymerase II promoter

Cellular Location

Nucleus. Associates to transcriptionally active chromatin but not at snRNA genes.

Involvement in disease

CHOPS syndrome (CHOPS): A syndrome characterized by cognitive impairment, coarse facies, heart defects, obesity, pulmonary involvement, short stature, and skeletal dysplasia.