Comparison of the high-mobility-group chromosomal proteins in rainbow-trout (Salmo gairdnerii) liver and testis

Abstract

Chromatography and characterization of the proteins extracted by 5% (w/v) HClO4 from rainbow-trout (Salmo gairdnerii) liver and testis show that the two tissues present a characteristically different spectrum of high-mobility-group (HMG) proteins. A variant subfraction of HMG C is found in liver, but is not detectable in testis, where even the main fraction of HMG C is present in only very low quantity. A protein, F, which appears to be related to protein H6 has similarly been isolated only from liver and not from testis. Quantification of the HMG proteins in total 5%-HClO4 extracts of trout liver and testis nuclei shows that, in relation to DNA, levels of HMG T1 and T2, and D are more than 2-fold, and C, 20-fold higher in liver than in testis. However, these differences do not result merely from the sequential withdrawal of HMG proteins at the same time that histones are replaced by protamines in the developing spermatid, since in testis, at some stages of maturation, levels of H6 are almost 2-fold higher than in liver. The implications of these findings for the function of HMG proteins are discussed.

Characterization and chromatin distribution of the H1 histones and high-mobility-group non-histone chromosomal proteins of trout liver and hepatocellular carcinoma

“…Since the electrophoretic patterns of liver HMG proteins shown in Fig. 5 were similar to those reported by Brown & Goodwin (1983), the HMG proteins were designated in accordance with the classification of these investigators. Liver contained HMG 14/17-like proteins D, C, H6 and F. G was a putative HMG protein.…”

“…Rainbow-trout liver and testis chromatin are associated with HMG TI and T2, which are similar to HMG 1 and 2, and HMG H6, which is similar to HMG 14 and 17 (Brown et al, 1980;Rabbani et al, 1980;Christensen & Dixon, 1981;Brown & Goodwin, 1983). In addition to these HMG proteins, it has been reported that trout liver chromatin contains HMG proteins C, D and F, which were either absent or present at very low levels in testis (Brown & Goodwin, 1983). However, other investigators did not find these 'liver-specific' HMG proteins (Christensen & Dixon, 1981).…”

Purification of non-histone acceptor proteins for ADP-ribose from mouse testis nuclei

“…The main point of difference is the lower concentration of proline found in mouse LMG proteins, although this may be a species variation. Phylogenetic differences have been noted for HMG proteins (Christensen & Dixon, 1981;Brown & Goodwin, 1983). Among the LMG-like proteins we have isolated, it is noticeable that proteins PD6, PD8 and PD9 have a similar amino acid composition, Mr and electrophoretic mobility on polyacrylamide gels at pH 2.9.…”

“…They present strong evidence that PSI, PS2 and PS3 are not degradation products of HMG-14 and -17 but favour the view that they are variant forms of the latter proteins. Brown & Goodwin (1983) have also isolated genuine variants of trout testis HMG-14 and -17. We consider it likely that a similar situation holds for SC2 and SC3.…”

“…Recently, interest has developed in the non-histone chromosomal proteins, known as the LMG and HMG proteins (Goodwin et al, 1973), as possible regulators of chromatin activity. HMG proteins have been investigated in considerable detail (reviewed by Johns, 1982) and have been found in all mammalian tissues examined so far with the exception of spermatozoa (Kennedy & Davies, 1980;Brown & Goodwin, 1983). The levels of HMG proteins 1 and 2 have been shown to vary significantly, not only between different tissues (Gordon et al, 1980;Mathew et al, 1981), but also between different physiological states of the same tissue (Seyedin & Kistler, 1979).…”