Zfp263, also known as NT2, is a zinc finger protein with a Krüppel-associated box (KRAB) domain. It functions as a negative regulator, and its role in gene regulation may be related to transcriptional repression. The KRAB domain has been implicated in transcriptional repression in many zinc finger proteins, suggesting Zfp263's potential involvement in regulating gene expression relevant to certain biological processes [1].

The study on Zfp263 (NT2) found that it binds to a specific 24 -bp sequence within the -530 -bp promoter segment of the alpha 2(XI) collagen gene (Col11a2). In situ hybridization in developing mouse cartilage showed an inverse correlation between NT2 mRNA expression (high in hypertrophic chondrocytes, low in resting and proliferating chondrocytes) and Col11a2 expression. Transfection of the NT2 expression vector in a chondrosarcoma cell line (RSC cells) inhibited Col11a2 promoter activity, while a mutant NT2 lacking the KRAB domain failed to do so. This indicates that Zfp263 (NT2) inhibits transcription of Col11a2, revealing a regulatory mechanism for cartilage-specific expression of Col11a2 [1].

In conclusion, Zfp263 (NT2) is a crucial negative regulator that inhibits the transcription of its target gene Col11a2, thereby playing an important role in regulating cartilage-specific gene expression. The findings from the study using cell-based and in situ analysis in mouse models contribute to understanding the regulatory mechanisms in cartilage development and potentially related cartilage-associated diseases [1].