Roles of the NFI/CTF gene family in transcription and development

The Nuclear Factor I (NFI) family of site-specific DNA-binding proteins (al so known as CTF or CAAT box transcription factor) functions both in viral D NA replication and in the regulation of gene expression. The classes of gen es whose expression is modulated by NFI include those that are ubiquitously expressed, as well as those that are hormonally, nutritionally, and develo pmentally regulated. The NFI family is composed of four members in vertebra tes (NFI-A, NFI-B, NFI-C and NFI-X), and the four NFI genes are expressed i n unique, but overlapping, patterns during mouse embryogenesis and in the a dult. Transcripts of each NFI gene are differentially spliced, yielding as many as nine distinct proteins from a single gene. Products of the four NFI genes differ in their abilities to either activate or repress transcriptio n, likely through fundamentally different mechanisms. Here, we will review the properties of the NFI genes and proteins and their known functions in g ene expression and development. (C) 2000 Elsevier Science B.V. All rights r eserved.