title: Ribosomal RNA and protein transcripts persist in the cysts of Entamoeba invadens.
abstract: In most organisms rDNA transcription ceases under conditions of growth stress. However, we have earlier shown that pre-rRNA accumulates during encystation in Entamoeba invadens. We labeled newly-synthesized rRNA during encystation, with [methyl-(3)H] methionine in the presence of chitinase to enable uptake of isotope. Incorporation rate reduced after 24h, and then increased to reach levels comparable with normal cells. The label was rapidly chased to the ribosomal pellet in dividing cells, while at late stages of encystation the ratio of counts going to the pellet dropped 3-fold. The transcript levels of selected ribosomal protein genes also went down initially but went up again at later stages of encystation. This suggested that rRNA and ribosomal protein transcription may be coordinately regulated. Our data shows that encysting E. invadens cells accumulate transcripts of both the RNA and protein components of the ribosome, which may ensure rapid synthesis of new ribosomes when growth resumes.
authors.affiliation: School of Environmental Sciences, Jawaharlal Nehru University, New Delhi 110067, India. Electronic address: sandy.mbt@gmail.com.
authors.forename: Sandeep
authors.initials: S
authors.lastname: Ojha
authors.affiliation: School of Environmental Sciences, Jawaharlal Nehru University, New Delhi 110067, India. Electronic address: j.ahamadjnu@gmail.com.
authors.forename: Jamaluddin
authors.initials: J
authors.lastname: Ahamad
authors.affiliation: School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India. Electronic address: alok.bhattacharya@gmail.com.
authors.forename: Alok
authors.initials: A
authors.lastname: Bhattacharya
authors.affiliation: School of Environmental Sciences, Jawaharlal Nehru University, New Delhi 110067, India. Electronic address: sbjnu110@gmail.com.
authors.forename: Sudha
authors.initials: S
authors.lastname: Bhattacharya
mesh_terms: D004747:Entamoeba / Q000235:genetics* / Q000254:growth & development* / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D008018:Life Cycle Stages; D015800:Protozoan Proteins / Q000235:genetics* / Q000378:metabolism; D016053:RNA, Protozoan / Q000235:genetics* / Q000378:metabolism; D012335:RNA, Ribosomal / Q000235:genetics* / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: D015800:Protozoan Proteins; D016053:RNA, Protozoan; D012335:RNA, Ribosomal
keywords: Cyst; Cyst RNA; Entamoeba invadens; Pre-ribosomal RNA; Pulse-chase; Ribosomal protein transcripts