The HIC1 gene extends approximately 15 Kbp and consists of four exons. The first three exons 1a, 1b and 1c are alternative. Note that exon 1a is included in exon 1c. The major transcripts are derived from alternative promoters associated with exon 1a and 1b. Exon 1c is conserved in rodent genomes (rat and mice) but transcripts containing it are very minor.
The fourth exon, exon 2, contains the coding region and the 3 untranslated region.
An in-frame upstream ATG initiation codon is also found in exon 1b. This upstream reading frame is conserved in mice.

3.0Kb mRNA.

No known pseudogene.

714 amino acids; around 80kDa; Transcription factor belonging to the BTB/POZ and Krüppel C2H2 zinc fingers family. There is no experimental evidence for the existence of a protein initiated by the upstream ATG (e.g. through the use of antipeptide specific antibodies).

Based on Northern Blots and RT-PCR experiments, HIC1 is widely expressed in various normal tissues.

Nucleus. Localized on nuclear dots upon overexpression by transient transfection assays in COS-7 or HEK293 cells. In human primary fibroblats (WI38), the endogenous HIC1 proteins are localized in discrete nuclear structures called "HIC1 bodies".

HIC1 is a transcriptional repressor belonging to the BTB/POZ and Krüppel C2H2 family (44 proteins in the human genome). HIC1 interacts with the corepressor CtBP through a conserved GLDLSKK motif in the central region. This central region also contains a SUMOylation site MK314HEP which is important for the transcriptional repression potential of HIC1. This K314 is also subject to a reversible acetylation/deacetylation implicating CBP/P300 and the NAD+ dependent class III deacetylase SIRT1.

HIC1 shares distant homology through the conserved BTB/POZ domain and C2H2 zinc fingers domain with several BTB/POZ transcriptional repressors.

No germinal coding sequence mutation have been described for HIC1.

No somatic coding sequence mutations have been described for HIC1 with one exception. During the screening of a panel of 68 medulloblastomas using SSCP analyses, a 12-bp deletion in the second exon of HIC1 has been identified. This results in a deletion of 4 glycine residues in a stretch of 8 located just after the BTB/POZ domain. The other regions of the protein specially the downstream central region and the zinc fingers domain are not affected by this deletion.

There are a number of reports highlighting differences in promoter methylation status in primary human tumours (breast, ovaries, prostate, .....) compared to matched normal tissues, hence the name of the gene.