RESUMO
Partial hepatectomy (P.H.) induces a partially synchronized growth response of liver under normal regulation of growth. In this phase changes in cellular morphology, radial distribution pattern of cells and other biological as well as major biochemical changes are well documented. Here, we have shown that the cellular content of UsnRNAs altered during this proliferative phase as well. The level of spliceosomal UsnRNAs (U1, U2, U4-U6) gradually decreased by 30-50% upto 48 hrs of P.H. followed by gradual increase to reach the normal level within one month of P.H. The U3 snRNA level on the other hand, was nearly equal to that in normal liver at 48 hrs of P.H. but in 24 and 72 hrs of P.H. its level was high (4 fold) in contrast to that in other UsnRNAs. Thus, it is clear from our data that the level of all the six UsnRNAs decreased during 48 hrs of P.H. compared to that after first 24 hrs. This has been correlated in the kinetics of UsnRNAs' synthesis (in terms of labelling) in isolated hepatocytes, where the rate of labelling of all the six UsnRNAs increased 20-30% in 24 hrs regenerating hepatocytes (R.H.) followed by sharp decrease by 30-50% within next 24 hrs, compared to that in the normal hepatocytes. But from 72 hrs onwards in R.H. the rate of labelling of all the six UsnRNAs again increased by 30-50% (compared to that in normal hepatocytes) followed by decrease of their labelling-rate to reach the normal level in R.H. within one month of P.H.(ABSTRACT TRUNCATED AT 250 WORDS)
Assuntos
Regeneração Hepática/fisiologia , RNA Nuclear Pequeno/biossíntese , Animais , Divisão Celular/fisiologia , Técnicas In Vitro , Fígado/citologia , Masculino , RatosRESUMO
Partial hepatectomy (P.H.) induces a partially synchronized growth response of liver under normal regulation of growth. In this phase changes in cellular morphology, radial distribution pattern of cells and other biological as well as major biochemical changes are well documented [24]. Here, we have shown that the cellular content of UsnRNAs altered during this proliferative phase as well. The level of spliceosomal UsnRNAs (U1, U2, U4-U6) gradually decreased by 30-50% upto 48 hrs of P.H. followed by gradual increase to reach the normal level within one month of P.H. The U3 snRNA level on the other hand, was nearly equal to that in normal liver at 48 hrs of P.H. but in 24 and 72 hrs of P.H. its level was high (4 fold) in contrast to that in other UsnRNAs. Thus, it is clear from our data that the level of all the six UsnRNAs decreased during 48 hrs of P.H. compared to that after first 24 hrs. This has been correlated in the kinetics of UsnRNAs' synthesis (in terms of labelling) in isolated hepatocytes, where the rate of labelling of all the six UsnRNAs increased 20-30% in 24 hrs regenerating hepatocytes (R.H.) followed by sharp decrease by 30-50% within next 24 hrs, compared to that in the normal hepatocytes.(ABSTRACT TRUNCATED AT 250 WORDS)
Assuntos
Regeneração Hepática/fisiologia , RNA Nuclear Pequeno/biossíntese , Animais , Divisão Celular/fisiologia , Técnicas In Vitro , Fígado/citologia , Masculino , Ratos , Fatores de TempoRESUMO
Limited digestion (2 min) of Sarcoma-180 nuclei by DNase-II released two nonhistone proteins from the hypersensitive sites of chromatin. The apparent molecular weights of these two proteins were 34 and 21 kDa. These proteins showed a moderate but specific inhibition in in vitro cell free transcription assay with native chromatin as template as opposed to no effect on native DNA transcription.
