In molecular biology, barrier-to-autointegration factor (BAF) is a family of essential protein

Protein

Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...

s that is highly conserved in metazoan evolution, and which may act as DNA-bridging proteins. BAF bind

Binding (molecular)

Molecular binding is an attractive interaction between two molecules which results in a stable association in which the molecules are in close proximity to each other...

s directly to double-stranded DNA, to transcription

Transcription

Transcription may refer to:*Transcription , a business which converts speech into a written or electronic text document*Transcription , software which helps convert speech into text transcript...

 activators, and to inner nuclear

Cell nucleus

In cell biology, the nucleus is a membrane-enclosed organelle found in eukaryotic cells. It contains most of the cell's genetic material, organized as multiple long linear DNA molecules in complex with a large variety of proteins, such as histones, to form chromosomes. The genes within these...

 membrane

Cell membrane

The cell membrane or plasma membrane is a biological membrane that separates the interior of all cells from the outside environment. The cell membrane is selectively permeable to ions and organic molecules and controls the movement of substances in and out of cells. It basically protects the cell...

 proteins, including lamin

Lamin

Nuclear lamins, also known as Class V intermediate filaments, are fibrous proteins providing structural function and transcriptional regulation in the cell nucleus. Nuclear lamins interact with membrane-associated proteins to form the nuclear lamina on the interior of the nuclear envelope...

 A filament

Protein filament

In biology, a filament is a "long chain of proteins, such as those found in hair, muscle, or in flagella". They are often bundled together for strength and rigidity. Some cellular examples include:*Actin filaments*Microtubules*Intermediate filaments...

 proteins

Protein

Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...

 that anchor nuclear-pore complexes in place, and nuclear LEM-domain proteins that bind to laminin

Laminin

Laminins are major proteins in the basal lamina , a protein network foundation for most cells and organs...

s filaments

Protein filament

In biology, a filament is a "long chain of proteins, such as those found in hair, muscle, or in flagella". They are often bundled together for strength and rigidity. Some cellular examples include:*Actin filaments*Microtubules*Intermediate filaments...

 and chromatin

Chromatin

Chromatin is the combination of DNA and proteins that make up the contents of the nucleus of a cell. The primary functions of chromatin are; to package DNA into a smaller volume to fit in the cell, to strengthen the DNA to allow mitosis and meiosis and prevent DNA damage, and to control gene...

. New findings suggest that BAF has structural

Secondary structure

In biochemistry and structural biology, secondary structure is the general three-dimensional form of local segments of biopolymers such as proteins and nucleic acids...

 roles in nuclear assembly and chromatin organisation, represses gene expression

Gene expression

Gene expression is the process by which information from a gene is used in the synthesis of a functional gene product. These products are often proteins, but in non-protein coding genes such as ribosomal RNA , transfer RNA or small nuclear RNA genes, the product is a functional RNA...

 and might interlink chromatin structure, nuclear architecture and gene regulation in metazoans

Animal

Animals are a major group of multicellular, eukaryotic organisms of the kingdom Animalia or Metazoa. Their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later on in their life. Most animals are motile, meaning they can move spontaneously and...

.

BAF can be exploited by retroviruses to act as a host component of pre-integration complexes, which promote the integration of the retroviral DNA into the host chromosome

Chromosome

A chromosome is an organized structure of DNA and protein found in cells. It is a single piece of coiled DNA containing many genes, regulatory elements and other nucleotide sequences. Chromosomes also contain DNA-bound proteins, which serve to package the DNA and control its functions.Chromosomes...

 by preventing autointegration of retroviral DNA. BAF might contribute to the assembly or activity of retroviral pre-integration complexes through direct binding

Binding (molecular)

Molecular binding is an attractive interaction between two molecules which results in a stable association in which the molecules are in close proximity to each other...

 to the retroviral proteins p55 Gag and matrix, as well as to DNA.