User:Keianahaigh/AF4/FMR2 family

Introduction
AF4/FMR2 (AFF) is a family of nuclear transcriptional activators that encourage RNA elongation. There are four genes in this family, all of which reside in the nucleus. The gene family includes AFF1/AF4, AFF2/FMR2, AFF3/LAF4 and AFF4/AF5q31. While different members of the AF4/FMR2 family are known for playing various roles in cells, they all commonly participate in the regulation of splicing and transcription.

AF4/FMR2 in Human Genes
Human genes include AFF1, AFF2, AFF3, and AFF4. Fusion genes involving AFF1 can produce a rogue activator leading to leukemia. Mutations in AFF2 are implicated in breast cancer. AFF2/FMR2 are found within the placenta and brains on the X chromosome. A trinucleotide repeat disorder involving AFF2 causes X-linked intellectual disability. This is due to the repetition of over 200 genes in the 5’ region of the untranslated helix. With overextension and methylation on this replicated gene (FRM1) is what leads to FRAXE ID - a rare human disease. This condition is known as FRAXE ID where the hippocampal region of the brain is affected in long term potentiation and it causes mental retardation. The FMR2 gene has been identified as a part of several pathways within the body (the transforming growth factor-β pathway, the Raf/MEK/MAP kinase pathway, and the P13K/PKB pathway). Studies have been performed on knockout mice to prove the detrimental effect it has on the body such as inflictions on organ growth, cell growth, and cytoskeletal structure.

AF4/FMR2 in Drosophilia
A Drosophila orthologue has been identified in relation to the AF4/FMR2 genes. Cells homozygous for a defective mutant of the gene are abnormally small, so the researchers named the gene Lilliputian (Lilli; Q9VQI9). It contains an AT-hook domain. It represents a novel pair-rule gene that acts in cytoskeleton regulation, segmentation and morphogenesis in Drosophila. Like Lilli, human AFF1 and AFF4 participate in the super elongation complex. The AFF1 and AFF4 proteins form this complex by linking positive elongation factor b (P-TEFb) and ELL1/2, which are two transcriptional elongation factors. These genes use chromatin remodeling and elongation to regulate transcription. The Lilli gene identifies the FMR2 functions that are possible, but not specific, in humans and mice.

References[edit] ^ Jump up to:a b

^ Jump up to:a b c

^

^

^ Gu Y, Nelson DL (2003). "FMR2 function: insight from a mouse knockout model". Cytogenetic and Genome Research. 100 (1–4): 129–39. doi:10.1159/000072847. PMID 14526173.

Bibliography[ edit]
DOI: 10.1093/hmg/ddr069

This article describes the functional characteristics of the AF4/FMR2 (AFF) family. It states how they are RNA-binding proteins and the ways in which the AF4/FMR2 family work within genes.

DOI: 10.1159/000072847

This article also describes the way in which the FMR2 gene works with transcription. The article uses a mouse model to predict possible functions of the gene within mice and humans.

DOI: 10.1038/boneres.2017.44

This article defines what the AF4/FMR2 gene does and how they function. The article goes into detail about proteins that belong to this family and their function.