11,000 ZR-75-1 breast cancer cell line: 260,000 MCF-7 breast carcinoma cell line Molecules/cell
||Human Homo sapiens
||Mark D. Biggin, Animal Transcription Networks as Highly Connected, Quantitative Continua, Developmental cell Volume 21, Issue 4, 18 October 2011, Pages 611-626 DOI 10.1016/j.devcel.2011.09.008 p.617 table 1 Table - link PubMed ID22014521
||Reese JC, Katzenellenbogen BS. Examination of the DNA-binding ability of estrogen receptor in whole cells: implications for hormone-independent transactivation and the actions of antiestrogens. Mol Cell Biol. 1992 Oct12(10):4531-8.PubMed ID1406642
||(primary source abstract:) "[Researchers] describe an assay employing the competitive binding of estrogen receptor (ER) with basal transcription factors on a constitutive promoter (cytomegalovirus-hormone response element[s]-chloramphenicol acetyltransferase [CMV-(HRE)n-CAT, containing a hormone response element(s) between the TATA box and the start site of transcription]) to examine the DNA-binding ability of the human ER in whole cells."
||"A survey of all credible published estimates that [Biggin] could find for four well studied species suggests that most animal transcription factors are expressed at 10,000–300,000 molecules per nucleus (Table 1). These estimates are further supported by [his] own experience and that of many other biochemists who have purified additional endogenous transcription factors with similar yields to the proteins in Table 1." "The data in Table 1 may be biased toward easily studied proteins, so the identification of transcription factors expressed at lower levels may identify better candidates for Coselective DNA Binding-based regulation."