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Research has been conducted on Sonic hedgehog signaling. Results demonstrate that Sonic hedgehog-dependent transcription factor Gli2 activation is important for epithelial homeostasis because of promoting proliferation via cell cycle regulators' transcriptional control.

Results indicate that requirements of individual D-cyclins, D1, D2, and D3, in a specific tissue is determined by transcription factors and as such not influenced by the properties of cyclins. In mice expressing only one cyclin type, the 'single-cyclin' embryos develop normally until late gestation and tissue-specific expression is lost.

Research demonstrates the existence of an intra-S-phase specific threshold, formed by DNA damage and stalled fork signals integration, in both wild-type and Origin Recognition Complex (ORC)2-1 cells. Data indicate that this threshold activates the CHK2-related kinase Rad53p kinase, which supports normal fork progression and toleration for damage-like DNA structures.

Mzf1 has been found using research in knockout mice to control tumorigenesis and cell proliferation in hemopoietic cells. Mzf1 can function as a tumor/growth suppressor in the hemopoietic compartment.

The p19(super.ARF) tumor suppressor and its p53-independent functions are discussed. Mice nullizygous for p53, ARF and Mdm2 were generated. Reintroducing ARF in cells without its only known target and the effects thereof were investigated. ARF-p53-Mdm2 appears to have a pathway that is not entirely straightforward. Where there is no Mdm2, p10ARF has been seen to interact with other targets to inhibit cell proliferation.

Matrix metalloproteinases (MMPs) are discussed as effectors of development and normal physiology in this review article. Topics include cell migration, tissue morphogenesis, extracellular matrix (ECM)-dependent cell proliferation and apoptosis, modulation of biologically active molecules, implantation, wound healing, mammary development, and bone development. MMPs are a family of extracellular proteinases sharing common functional domains and activation mechanisms.

Regulated initiation of translation from varied sites has been shown to be the main mechanism for generation of different protein isoforms from C/EBP(alpha) and C/EBP(beta) mRNAs. The regulated expression of different C/EBP isoforms depends on the integrity of evolutionarily conserved upstream open reading frames in C/EBP(alpha) and C/EBP(beta) mRNAs. Regulation of translation initiation that determines C/EBP isoform ratio has a vital role in control of cell proliferation and differentiation in C/EBP(alpha)- and C/EBP(beta)-expressing cells.

CREB binding protein (CBP) and p300 and the complexes processes they participate in in cell growth, development, and transformation are discussed in this review article. The two proteins seem to be able to contribute to diametrically opposed cellular processes. They work in various tumor-suppressor pathways. They are also, as coactivators, essential for functions of many oncogenes. Whether they are part of apoptosis or cell proliferation seems to be very context-dependent.

Research shows that beta1-integrin mutant chondrocytes fail to form columns during growth, exhibit marked proliferation defects that affect several phases of the cell cycle. Results demonstrate that beta1-integrin-dependent motility and chondryocyte proliferation are essential for endochondral bone formation.

Research shows that the nuclear factor kappa B (NF-kappaB) modulates mesenchymal-derived cell lineage differentiation through posttranscriptional down regulation of developmental regulators in response to cytokine signaling. Furthermore, it inhibits chondrogenesis and destabilizes transcription factor Sox9 mRNA.

Human Sin3 deacetylase and trithorax-related Set1/Ash2 histone H3-K4 methyltransferase have been found to be linked selectively by HCF-1, the cell-proliferation factor . It appears, based on ana lysis of HCF-1, that it can regulate transcription positively/ne gatively in a broa d way via selective modulation of chromatin structure. Regions of HCF-1 critical for its role in cell proliferation associate withthe Sin3

Caspases have been found to signal apoptosis and also antigen-induced activation in immune system cells and caspase 8 is critical for both activation and death of cells of the immune system , a paradox. C aspaces, especially caspase 8, may have a role in the immune system promoting lymphocyte activation and proliferation.